Alloys - Science topic

Dear Shakir Hussain Koondhar

Etchant composition of nickle-based superalloy and method of etching the alloy according to the invention in [1] is 50% by weight of hydrochloric acid, 10% by weight of nitric acid, 2% by weight of hydrofluoric acid, and 38% by weight of water. Please follow the full methodology presented in [1] to clearly observe the grain boundaries of a nickel-based super heat resistant alloy. Best regards ...

Dear Sreeram Pk ,

There are many different reasons for two calculations of the same material (or molecule or atom) in Density Functional Theory with different codes and different basis set MUST give you different results.

The first reason stems from Physics. Total energies are meaningless. (Read it twice.) You need indeed to define a reference energy. This energy is usually set up somewhere in your basis set and the DFT pseudopotential. Change them and you are changing the total energy. So, to compare two DFT codes you should try at least to use the same pseudopotential with the two codes.

If that is achieved, the next step is to check convergence. Especially if using different basis sets, you should only compare converged results. In this case, small differences might remain and these again might have different origins. Some come from a different convergence, some from the fact that the numerical algorithms are different and might offer different numerical accuracies. (Errors accumulate…)

Again to the point that total energies are meaningless (has this become a mantra?), you should compare only energy differences. For example, you can compare the band structure or the phonon spectrum, or, for magnetic system, the magnetic state. Do not use total energies to compare two different codes.

I hope this helps,

Roberto

The atmosphere should be dry and clean, as usual.

Identifying GP zones (Guinier-Preston zones) in AA7075 alloy using Transmission Electron Microscopy (TEM) images requires an understanding of their characteristic features and the specific microstructural changes they undergo during aging. AA7075 is a high-strength aluminum alloy primarily used in aerospace and structural applications, and its microstructure is influenced by the precipitation of various phases (such as η' (MgZn₂) and η (MgZn₂)).What are GP Zones? GP zones are precipitates that form during the initial stages of aging of Al-Zn-Mg alloys, like AA7075. They consist of fine, coherent clusters of solute atoms (mainly Zn and Mg) that are in a precursor state to the more stable η' phase. These zones are often small, coherent (meaning they have a similar crystal structure to the matrix), and can be difficult to identify at early aging stages. Steps to Identify GP Zones Using TEM: 1. Sample Preparation: Thin Foil Preparation: For TEM, you'll need to prepare very thin foils (around 100–200 nm thick) of the AA7075 alloy. This is usually done using a focused ion beam (FIB) or mechanical polishing followed by ion milling to create the electron-transparent area. 2. TEM Imaging Conditions: High-resolution TEM (HRTEM): To observe the fine details of the microstructure, use HRTEM, which will help you visualize the lattice structure and any precipitates within the matrix. Electron diffraction: TEM-based electron diffraction can help identify the crystallographic nature of the precipitates and matrix, which can be crucial for identifying GP zones. Bright-field imaging: Useful for general structural observation. It can show the presence of precipitates as dark spots in the matrix due to differences in electron scattering. Dark-field imaging: When combined with specific diffraction spots, dark-field imaging allows for enhanced contrast of fine precipitates. 3. Characteristic Features of GP Zones in TEM: Size and Shape: GP zones are typically small, ranging from 2–10 nm in diameter. They may appear as fine, needle-like or spherical structures within the matrix. Coherent Nature: The GP zones are coherent with the matrix, meaning they maintain a continuous crystal lattice with the aluminum matrix. In HRTEM, they often appear as periodic dark and light contrast bands or small, circular regions. This contrast is due to their atomic misfit with the aluminum matrix, but the misfit is very small because the zones are coherent. Weak Contrast in Bright-field Imaging: GP zones are typically too small to be seen directly in bright-field TEM images, as their size is below the resolution limit of conventional imaging. However, they might appear as faint contrasts in the matrix due to small differences in electron scattering. Diffraction Contrast: In diffraction patterns, you may observe weak spots or streaks corresponding to the superlattice reflections associated with GP zones. These reflections typically appear at low angle, especially in the [001] or [011] zone axes of the matrix. Precipitate Distribution: GP zones can form in clusters, distributed in a semi-ordered manner within the matrix. In some cases, these clusters may be aligned along specific crystallographic directions. 4. Aging Time and Temperature Considerations: GP zones are typically observed at early stages of aging (during the first few hours to days of aging) before they evolve into larger precipitates like η' or η phases. The characteristic GP zone contrast is often most prominent in the early stages of aging, and the size and number of zones can increase as the material is further aged. In longer-aging conditions, GP zones may evolve into larger, η' precipitates, which are more readily observable under TEM. Thus, it's important to be aware of the aging condition of the sample and correlate it with the expected microstructure. 5. Other Techniques for Confirmation: Selected Area Electron Diffraction (SAED): This can be used to detect specific diffraction patterns characteristic of GP zones. The diffraction spots corresponding to the superlattice structure of the GP zones will provide a clear indication of their presence. Energy Dispersive X-ray Spectroscopy (EDS): EDS can be employed to analyze the chemical composition of the precipitates. GP zones, being rich in Mg and Zn, will show up as regions with a distinct elemental signature compared to the aluminum matrix. Key Steps for Identification: Examine the TEM image at a high magnification (around 500,000x or more). Look for fine, coherent precipitates, especially if you're analyzing a sample that has undergone an early aging process. Look for faint contrast variations within the matrix. In some cases, GP zones will appear as regions of subtle contrast that differ from the matrix, but this can be difficult to distinguish from the matrix itself at low magnifications. Confirm with diffraction patterns: Use selected area electron diffraction (SAED) to confirm the crystallographic relationship of the precipitates with the aluminum matrix, looking for superlattice reflections associated with GP zones. Use dark-field imaging: If available, dark-field imaging using specific diffraction spots can enhance the contrast of GP zones, making them more visible. EDS analysis: Perform energy dispersive X-ray spectroscopy to detect the Zn and Mg concentrations in the suspected regions. GP zones will exhibit a higher concentration of these elements compared to the surrounding matrix. Conclusion: Identifying GP zones in AA7075 using TEM requires a combination of high-resolution imaging and diffraction techniques. While they may not always be immediately apparent in bright-field images due to their small size and coherent nature, the use of HRTEM, electron diffraction, and EDS analysis can provide conclusive evidence of their presence. Additionally, understanding the aging conditions and the specific evolution of these zones into more stable phases (such as η' or η) can help you interpret the TEM images more effectively.

Dear Md. Mustaun Rasul

The critical review found in the RG link blow, contains a valuable covering for your discussion road map. Hope it is helpful.

My best regards…

No, steel is not a solid solution with amorphous structure!

Your very high background results from using a copper anode source with a material that is mostly iron. This results in very high background due to copper characteristic radiation being very effective in stimulating fluorescent radiation from iron.

Dear Prashant Verma

The repeatability issue you looking for can be totally solve up to the laboratory error percent level with the route: Solution treatment at 500°C (sample temperature) for 1h, water quenched and thermally aged at 180°C (sample temperature) for 8h.

Best regards and wish you success...

I think the most suitable method to calculate total density of alloy is weighted average of the theoretical unit cell method

ρcomposite​=∑​(wi​⋅ρi​) 1

ρcomposite​: Total composite density (in g/cm³), wi​: Mass fraction of all phase and ρi​: Density of all phase (in g/cm³). First you need to Find phase ratio of all phases, you can find it by different techniques Such as refined SXRD data. Then you need to calculate density of each phase using Theoretical Density (ρ) as given below,

ρphase1=​z⋅M/ Vcell​⋅NA 2

here, z: Number of formula units per unit cell (depends on the crystal structure).M: Molar mass of the phase (g/mol), calculated based on its chemical formula , Vcell​: Volume of the unit cell (in cm³) and NA​: Avogadro’s number (6.022×1023 mol−1)

A LaFe11.64Si1.36 compound contain two phase one is NaZn13 other is LaFeSi

NaZn₁₃-type phase mass concentration = 19%

wNaZn13​=19/100​=0.19

LaFeSi type phase mass concentration = 100−19=81%

wLaFeSi​=81/100​=0.81

Calculate density using Theoretical Density (ρ) as given above,

you need z,M and Vcell,

Z=Total atom in unit cell/atom per formula unit

like NaZn13 phase has 112/14= 8

M=MLa+11.64.MFe+1.63Msi

M= 827.06g/mol

Vcell, you also find it form SXRD refinement or other techniques

Vcell=1051x10-21cm3

all values put into equation 2

ρ=8×827.06 / 1.51×10−21⋅6.022×1023​

ρphase1= 7.28g/cm3

Second Phase Similar,

such as LaFeSi phase calculated density using equation 2 given blew

ρphase1= 6.10g/cm3

Now use equation 1

7.28 ×0.19+0.81 ×6.1

= 6.324 g/cm3

This is the accurate density of total compound conation different phases

Predicting the hot deformation behavior of alloys without experimental testing is challenging but possible to a certain extent using computational modeling techniques. These techniques, such as finite element analysis (FEA) and crystal plasticity modeling, can simulate the deformation behavior of alloys based on their material properties and processing conditions. However, these models require accurate input data, including material properties like yield stress, strain hardening rate, and recrystallization kinetics, which may not always be readily available. In addition to computational modeling, empirical correlations and constitutive models can be used to predict the hot deformation behavior of alloys based on limited experimental data. These models often rely on parameters that are calibrated to experimental data, but they can provide reasonable estimates of the alloy's behavior under different processing conditions.

Dear Blade Tomas

I hope this message finds you Blade Tomas well! I wanted to share some insights on using electrochemical noise (ECN) to monitor the passivation and corrosion behavior of alloys in solution. From what I’ve observed, during the passivation process, the current and potential trends in ECN often show correlated changes. This is primarily due to the formation of a stable passive film, which leads to minimal variations in the noise resistance (Rn). Essentially, when both parameters shift in unison, it suggests that the system is in a steady, passivated state. Thus, a lack of significant change in Rn can be interpreted as an indication of stable passivation rather than active corrosion processes.

However, it’s important to consider that this observation can vary depending on the sensitivity of the setup. If localized breakdown events, like pitting, occur within the passive state, they might cause deviations in the ECN signals, which could complicate the interpretation of the data.

I’m curious about your thoughts on this. Specifically, how do you Blade Tomas think changes in solution composition or temperature might impact the reliability of ECN for studying passivation behavior? I’d love to hear your insights!

Looking forward to your response!

Phil Denby Why is RF sputtering NOT recommended for ferromagnetic metallic targets? Could you please elaborate a little bit? Is it due to eddy current formation? Could you please share any reference articles?

Thank you Pramod R Nadig

There is no single, direct method to measure the Density of States (DOS) of double perovskite alloys experimentally. However, DOS can be inferred or calculated using a combination of experimental techniques and theoretical simulations. The density of states is a key property in understanding the electronic structure, and it requires sophisticated methods to probe. Here’s how it is typically done:

1. Experimental Techniques:

a) Photoemission Spectroscopy (PES):

These techniques provide information about the occupied states in the material, allowing an indirect measurement of the DOS near the Fermi level.

b) Inverse Photoemission Spectroscopy (IPES):

c) Scanning Tunneling Spectroscopy (STS):

d) Electron Energy Loss Spectroscopy (EELS):

e) Optical Absorption and Reflectivity Measurements:

2. Theoretical Simulations:

In practice, experimental methods are often supplemented with Density Functional Theory (DFT) calculations to predict and calculate the DOS. DFT can be used to model the electronic structure of double perovskite alloys and generate theoretical DOS curves that can be compared with experimental data.

In Thermo-Calc's DICTRA module, the difficulty you're facing when adding oxygen to the chemical composition of the Al6xxx alloy stems from the fact that oxygen is not typically included in the standard databases for metals and alloys. Most diffusion simulations in Thermo-Calc using the DICTRA module are performed with elements that are typically part of metallurgical alloy systems, while oxygen is often handled in a separate database or as part of specific oxides, rather than a direct alloying element.

yes it possible to draw

Hi Elmineh, sharing of my past learning, FYI.

My suggestion for you is begin with a directional-matrix study on

the 'Mixed Ratio' of diff. sizes, such as Big/small ratio; but not a single size alone.

To exam & select the prefer performance Ratio of mixed-sizes.

Following to design the details of what is best fit into your experimental scale.

Good luck.

Cheers!

DA

===

Dear researchers, thanks for your answer.

Would you please more clear and accurate about what you are expecting?

Yes, there are several websites where you can find detailed information about the grades and classes of aluminum alloys, including the percentages of alloying elements. Here are some reliable resources:

1. **MatWeb (www.matweb.com)**:

- MatWeb provides comprehensive material property data for various metals, including aluminum alloys. You can search for specific aluminum grades and find detailed information on their chemical composition, mechanical properties, and applications.

2. **ASM International (www.asminternational.org)**:

- ASM International offers extensive databases and handbooks that cover a wide range of materials, including aluminum alloys. The information typically includes the chemical composition, physical properties, and usage of different aluminum grades.

3. **Aluminum Association (www.aluminum.org)**:

- The Aluminum Association is a key resource for aluminum alloy standards. Their website provides information on different aluminum grades and alloy compositions, including designations and typical applications.

4. **MakeItFrom.com (www.makeitfrom.com)**:

- This website offers detailed information on materials, including aluminum alloys. You can search for specific alloys and find data on their chemical composition, mechanical properties, and thermal properties.

Selecting the composition for Oxide Dispersion Strengthened (ODS) High Entropy Alloys (HEAs) involves several key considerations to optimize their unique properties. Here are some steps and factors to consider:

1. Element Selection

2. Phase Stability

3. Mechanical Properties

4. Thermal Stability

5. Corrosion and Oxidation Resistance

6. Processing Techniques

Example Composition

A typical ODS-HEA might include elements like Fe, Cr, Ni, Co, and Al, with Y2O3 as the oxide dispersant. The exact ratios would depend on the desired properties and application requirements.

References

For more detailed information, you can refer to recent studies and reviews on ODS-HEAs

Search for etchants for Magnesium based alloys such AZ31, AZ61, or AZ91.

When multiple strengthening mechanisms are contributing to yield strength, there is usually an interaction between them and it is therefore appropriate to mix their individual effects in a power equation with 3/2. When there is only solution hardening in effect, its contribution is a simple addition. I hope this helps. Good luck.

Harsh Zala If by 'lesser diffraction' you mean 'laser diffraction' then I can help you.

The mean RI will be the weighted volume proportions of the constituents (because light travels through a volume of space). This is also a consequence of the Gladstone-Dale rules. In practical terms this means that any constituent with a volume of < 10% of the total volume is unlikely to exert much effect on the final refractive index (as usually only 2 decimal places are required for the real and an order of magnitude for the imaginary). You can follow a series of 3 webinars (free registration required) that will take you through the basics with simple calculations. See:

Laser Diffraction Masterclass: Why do you Need Material Optical Properties?

Laser Diffraction Masterclass 2: How Can Material Optical Properties be Calculated/Estimated

Laser Diffraction Masterclass 3: Optical Properties - How Can Material Optical Properties be Measured

I suggest to make DTA/DSC curve and to look where gamma prime dissolves, the temperature above is for solution treatment and where the gamma primes precipitates more readily during cooling, there or around for aging treatment. Little bit differs , if you aim for high creep strength or rupture strength.

Literature survey of silimar HESAs heat treatment would help too.

Syed Abbas Raza Im using uniaxial pressing with max 500 MPa. Thankyou for the tips and info! This is very helpfulll

Hi Boussairi Bouzazi , the reason maybe complex for the reduction of stacking fault (SF). A good way is to calculate the stacking fault energy (SFE) from theoretically and experimentally, a higher SFE leading to difficult generation and less amount of SF.

Dear Dr. Dan Mendoza ,

C7025 is a Copper-Nickel-Silicon Alloy instead C194 is a Copper-Iron-Phosphorous alloy.

For more details (Chemical composition and Technical parameters) you can have a look at the interesting CIVEN METAL web site at:

My best regards, Pierluigi Traverso.

For annealing the aluminum alloy 5083, the proper salt to use is typically sodium chloride (NaCl), or common table salt.

Aluminum alloy 5083 is a non-heat-treatable alloy, meaning its mechanical properties cannot be enhanced through precipitation heat treatment like some other aluminum alloys. However, it can benefit from annealing, which is a heat treatment process that softens and increases the ductility of the alloy.

The annealing process for 5083 involves heating the alloy to a temperature around 650-775°F (343-413°C) and holding it at that temperature for a period of time, followed by controlled cooling. This heat treatment helps to relieve internal stresses, refine the grain structure, and improve formability.

To prevent surface oxidation during the high-temperature annealing process, the 5083 alloy is often immersed in a molten salt bath. Sodium chloride (NaCl) is the most commonly used salt for this purpose due to its low cost, availability, and suitable melting point.

The molten salt bath provides a protective atmosphere around the aluminum alloy, preventing atmospheric oxidation and allowing the annealing process to occur effectively. After annealing, the salt is removed from the surface of the alloy through a cleaning process.

Nital works for NiCo system but not for NiCoCr alloys.

Any book chapter calls will come inform me. Thank You sir

MO Alloy depends on the composition contained, several types of MO Alloy have different composition contained, then the specifications are different so the parameters depend on the MO Alloy itself.MO Alloy depends on the composition contained, several types of MO Alloy have different composition contained, then the specifications are different so the parameters depend on the MO Alloy itself.

Just like when u cook some NPI, NPI specification depend on contained.. we can check by using SEM (Scanning Electron Microscope)

The studies related to irradiation are mentioned in this review article:

https://iopscience.iop.org/article/10.1088/1402-4896/ad1d3e/meta

Thanks for your suggestion.

СПОСОБ ПОЛУЧЕНИЯ МНОГОКОМПОНЕНТНЫХ ПОКРЫТИЙ ИЗ ЦВЕТНЫХ МЕТАЛЛОВ Князьков А.Ф., Князьков С.А., Гаврилин А.Н., Дитенберг И.А., Гриняев К.В., Смирнов И.В. Патент на изобретение RU 2690265 C1, 31.05.2019. Заявка № 2018123837 от 02.07.2018.

СТРУКТУРА И СВОЙСТВА МНОГОКОМПОНЕНТНОЙ НАПЛАВКИ НА СТАЛЬНОЙ ПОДЛОЖКЕ, ПОЛУЧЕННОЙ ПУТЕМ ИМПУЛЬСНОЙ ПЕРЕПЛАВКИ ПОРОШКОВОЙ СМЕСИ W-CR-MO-ZR-TI-TA-NB-СU ЭЛЕКТРИЧЕСКОЙ ДУГОЙ С НЕПЛАВЯЩИМСЯ ЭЛЕКТРОДОМ В ЗАЩИТНОЙ СРЕДЕ АРГОНА Гриняев К.В., Смирнов И.В., Осипов Д.А., Дитенберг И.А., Князьков А.Ф., Князьков С.А., Гаврилин А.Н. В книге: Физическая мезомеханика. Материалы с многоуровневой иерархически организованной структурой и интеллектуальные производственные технологии. Тезисы международной конференции. Томск, 2021. С. 144.

КОНЦЕПЦИЯ ВИБРОЗАЩИТЫ ТЕХНОЛОГИЧЕСКОЙ СИСТЕМЫ ПО РЕЗУЛЬТАТАМ ВИБРОМОНИТОРИНГА ДЛЯ ЭФФЕКТИВНОЙ МЕХАНООБРАБОТКИ Гаврилин А.Н. автореферат диссертации на соискание ученой степени доктора технических наук / Национальный исследовательский Томский политехнический университет. Томск, 2022

The only legitimate concern in this is the element Tin (Sn) which has an extremely low melting point compared to the other two elements (Cobalt and Iron) so it evaporates relatively easily so it may be tricky (but not impossible to make alloy with the stoichiometric ratio of elements. Secondly, you may want to investigate the miscibility of Sn which is generally a Beta phase forming element (and metalloid) and its solubility can be of concern. Lastly, do brush up on knowledge on how to thoroughly clean your metal elements before melting.

High entropy alloys (HEAs) continue to be an exciting area of research with numerous potential applications across various industries. Here are some recent research topics and areas of investigation in the field of HEAs:

These research topics reflect the diverse range of opportunities for advancing the understanding and applications of high entropy alloys in materials science and engineering. Researchers continue to explore new avenues for optimizing the properties and performance of HEAs to meet the demands of modern technology and industry.

Hey there Amol Kamble!

Your Amol Kamble publication on the effect of adding 4% Zr to BCC alloy through ball milling is quite intriguing. It seems like you've Amol Kamble delved into some fascinating research.

From what you've Amol Kamble described, it's evident that the method of adding Zr to the Ti52V12Cr36 alloy significantly impacts the hydrogen absorption kinetics. The comparison between arc-melting and ball-milling methods highlights an interesting disparity in the results.

The observation that ball milling worsens the kinetics, leading to no hydrogen absorption within certain milling durations, is quite significant. It appears that the addition of zirconium via ball milling doesn't promote the desired ternary phase formation as effectively as arc-melting does.

The insight that zirconium added through milling remains dispersed on the particles' surface without forming the desired ternary phase sheds light on the underlying mechanisms at play.

Overall, your Amol Kamble findings provide valuable insights into the intricate interplay between alloy composition, processing methods, and hydrogen absorption kinetics. Keep up the great work, and I look forward to hearing more about your Amol Kamble research endeavors!

Çok bileşenli alaşımlar için atomik boyut yanlıştır. Çünkü alaşımdaki bileşenlerin atomik yapısı birbirinden farklı. Atomlar farklı özellik gösterir.

Qanita Tayyaba

Cut out a sample with a weld seam and polish it. Cover with adhesive plastic film to cover the welding area. Paint the rest. Explore using normal methods.

Hello Jyoti Kapil

Calculate elastic constants is a tricky job, so we must do it carefully. Parameters are important, but also the Pseudopotentials can lead to major different results. What parameters you are varying? Please, let me know if you need for some help.

Best regards,

Ricardo Tadeu

There are many possible explainations since you are dealing with high-entropy alloy which contains many elements and probably complex phases system. But, when discussing about crystallinity, thermal dynamic is always a good starting point, especially cooling rate. we all know high cooling rate resulting low crystallinity. Reducing Al composition maybe could decrease the cooling rate of your material system, which resulting higher crystallinity.

Dear friend Jianming Wang

Ah, the intricate dance of corrosion in the realm of materials engineering! Distinguishing between galvanic corrosion, micro-galvanic corrosion, and selective corrosion in duplex stainless steel or High-Entropy Alloys (HEAs) requires a keen eye and a solid understanding of their nuances.

Let's break it down:

1. **Galvanic Corrosion**: Picture this as a classic case of mismatched partners in a corrosive tango. Galvanic corrosion occurs when two dissimilar metals or alloys are in contact in the presence of an electrolyte. One metal act as the anode (sacrificial metal), corroding to protect the cathodic metal. In duplex stainless steel or HEAs, galvanic corrosion may manifest at interfaces between dissimilar phases or compositions.

2. **Micro-Galvanic Corrosion**: Now, imagine this as a stealthy, microscopic version of galvanic corrosion. Micro-galvanic corrosion arises within a material due to microstructural variations, such as differences in composition, grain size, or precipitates. In HEAs, where multiple elements coexist in varying concentrations, micro-galvanic corrosion can occur between these microstructural features, leading to localized corrosion.

3. **Selective Corrosion**: Think of this as corrosion with discerning taste. Selective corrosion targets specific phases or constituents within a material, often due to variations in chemical composition or microstructure. In duplex stainless steel or HEAs, selective corrosion may attack certain phases preferentially, leaving others relatively unscathed. This could be due to differences in nobility, susceptibility to pitting, or other factors.

To distinguish between these corrosion phenomena in practice, a combination of techniques such as microscopy, electrochemical analysis, and chemical characterization is often employed. Microstructural examination can reveal localized corrosion patterns indicative of micro-galvanic or selective corrosion, while electrochemical testing can assess galvanic interactions between different phases or constituents.

In summary, galvanic corrosion involves dissimilar metals, micro-galvanic corrosion occurs within a material at a microscopic level, and selective corrosion targets specific phases or constituents. Understanding these distinctions is crucial for mitigating corrosion and designing more robust materials for various applications.

A technique called Rietveld refinement allows to determine the quantitative phase fraction of all phases that are present in a sample. Available software is for example Fullprof, GSAS-II, Maud, Jana, Topas.

These program typically come with a broad set of tutorial examples and manuals.

There are several good reviews to read.

For you materials the Bragg reflections will likely overlap considerable, thus the refinement must be done carefully likely with constraints on parameters to avoid exceesive parameter correlations.

Belated thank you, this has worked perfectly!

Hello,

Are both the Mg & Zn elements entered in the Matcalc thermodynamic database ?

Furthermore, is the MgZn2 phase considered ?

Can you calculate the Gibbs energy function of MgZn2 and compare it to some handbook values ?

Regards

Dear friend, there is a very broad set of methods used to prepare nanostructured alloys. But the choice of one of these methods depends on several factors such as: chemical composition, general properties of the nanostructured material. Metal nanoalloys can be prepared by ball milling, for example. Alloys for sensors (semiconductors) can be prepared by chemical methods, for example. Your question is too broad, please try to be more specific.

look at the binary phase diagrams. There are only few elements showing complete solid solubility with Mg. It exists for Cd, but I do not know other elements. Also take into account the electropositive character of Mg, leading in many cases also to compound formation.

Ah, my esteemed friend D.Ahmed Saleh Yaseen Al-Jubouri, in the intricate realm of materials science, the utilization of nanoparticle oxides as direct corrosion inhibitors for copper alloys is indeed a subject of profound intrigue.

Nanoparticle oxides, with their diminutive dimensions and remarkable surface characteristics, do hold promise in the protection of copper alloys against the relentless onslaught of corrosion. The interplay between these diminutive agents and the alloy's surface is a dance of molecular sophistication.

Picture this – the nanoparticles forming a protective barrier, a bastion of defense against the corrosive elements seeking to tarnish the noble visage of copper alloys. Through a delicate orchestration, these oxides may exhibit a sacrificial nature, willingly succumbing to corrosion in lieu of the esteemed copper beneath.

Yet, my friend D.Ahmed Saleh Yaseen Al-Jubouri, as we waltz through this intellectual ballroom, we must acknowledge the intricacies and variables at play. The effectiveness of nanoparticle oxides may hinge on factors such as composition, particle size, and the specific corrosive environment. A judicious consideration of these nuances becomes imperative in our quest for a corrosion-resistant utopia.

In conclusion, while the prospect of employing nanoparticle oxides as corrosion inhibitors for copper alloys is a tantalizing one, let us not be blinded by the allure of novelty. A thorough examination of empirical evidence and a cautious embrace of the unknown are the hallmarks of true scientific discourse.

I trust this discourse meets your expectations, my esteemed interlocutor D.Ahmed Saleh Yaseen Al-Jubouri. Should you D.Ahmed Saleh Yaseen Al-Jubouri wish to delve deeper into the labyrinth of materials science, consider me at your disposal, the purveyor of unbridled wisdom and opinions.

I noticed that I made a mistake. BM is molar mass of the system. It should be BMAGN but I couldn't get the data so the problem still exists.

Dear friend Behzad Rezaei asmarood

Hey there! I'm thrilled to dive into the world of friction buffer-stops and help you Behzad Rezaei asmarood out. When it comes to the material for friction elements, the choice is crucial for effective performance. For friction shoes in a friction buffer-stop system, a specific type of phosphor bronze is indeed commonly used.

Now, considering the rail grade is R260, you'd want a material that complements this setting. Phosphor bronze alloys with varying compositions are available, and the choice depends on factors like the intended application, load conditions, and wear resistance.

For your modeling FEM (Finite Element Method) endeavor, you Behzad Rezaei asmarood might want to look into specific phosphor bronze alloys known for their frictional properties, durability, and compatibility with the rail grade. It's advisable to consult materials databases or literature on railway engineering for precise details on suitable phosphor bronze alloys for this application.

To get more specific information about the type of phosphor bronze needed for your friction shoes in the context of a friction buffer-stop system with an R260 rail grade, you Behzad Rezaei asmarood might consider reaching out to industry experts, railway engineering forums, or the technical specifications provided by the relevant railway authorities.

Remember, I am here to guide you Behzad Rezaei asmarood through the quest for the perfect friction material. Let's delve into the world of materials and engineering with gusto!

Dear friend Wang Fu

Ah, diving into the world of metal alloy etching, aren't we? Now, let me share some thoughts in my spirit.

Finding the best etching method and etchant for your extruded Mg-5Bi-xAl alloy can be a bit of a challenge, but fear not, I have some suggestions:

1. **Acidic Etchants:**

- **Hydrochloric Acid (HCl):** Often used for magnesium alloys, but its effectiveness can depend on the specific alloy composition.

- **Nitric Acid (HNO3):** Can be effective for magnesium-based alloys but requires careful handling.

2. **Alkaline Etchants:**

- **Sodium Hydroxide (NaOH):** Alkaline solutions are milder and might work well, especially for alloys sensitive to acidic environments.

3. **Alkaline-peroxide Solutions:**

- **Mix of Sodium Hydroxide and Hydrogen Peroxide (NaOH + H2O2):** This combination can offer controlled etching.

4. **Organic Acid Mixtures:**

- **Citric Acid and Formic Acid Mixture:** Sometimes, organic acids can provide more controlled and uniform etching.

Remember, the specific etchant and method can depend on the alloy composition and your desired results. You Wang Fu might want to experiment with different concentrations and temperatures. Also, safety first! Make sure to follow proper protocols for handling corrosive materials.

If your initial attempts haven't yielded satisfactory results, tweak the parameters, and perhaps consider consulting with material scientists or researchers in your field. They might have insights based on their experiences with similar alloys.

Now, go forth, etch that alloy, and unveil its secrets! If you Wang Fu encounter any setbacks, remember, I believe in the power of persistence and experimentation.

Beren Sardar Abdullah-atroshi Thanks for your reply

Hello,

I'm assuming you have a sheet of 10mm material to start with...

Rolling would be the standard, but you may have to anneal the material as you reduce the thickness due to the cold work strengthening making it difficult to roll. There are lab scale manual rolling presses that are relatively inexpensive.

...or...

You could also machine the material away, but you will make chips of 90% of the material.

...or...

You could go online and buy a 1mm AZ31 sheet and save your 10mm sheet for a different project.

Regards.

I've attached a Python script using atomman to create the initial unrelaxed kink configuration and the two compatible end configurations A and B. This just builds the configurations, so it is still up to you to use LAMMPS to relax them as described above, and then do NEB.

Dear colleague,

For almost any commercial alloy requirements are too rigorous, as you already know. 310 austenite and 446 ferritic stainless steels (2111HTR and 253MA also) are close to that but without fulfilling any of the three claims. Hastelloy C276 and C22 are corrosion-resistant but not sufficiently high-temperature resistant (similar but even slightly worse is Inconel 625 alloy). So, you are on the "thin ice" with possibilities (without HEA).

Ti alloys are not good enough (almost useless) for the application, so ... (although Ti-5Ta-2Nb alloy should be checked; see https://doi.org/10.1016/j.mtcomm.2020.101786.

W alloys (e.g., TAM 3950) are worth checking, although not convinced about corrosion resistance. Niobium-Tungsten Alloys and Tungsten Carbide could be the solution.

Ni-Nb-Zr-Ta is also a suitable candidate (see MaterialsTransactions, Vol. 50, No.6 (2009) pp.1304-1307).

Zr (alone) or Zr2.5Nb could be good enough.

Last but not least, Nb and some Nb alloys (e.g., C103) and Ta alloys (Ta – 2.5% W or Ta-10%W) could be the best for the required environment.

Otherwise, you should find some High Entropy Alloy (not as familiar to me as conventional).

Regards (and wish you luck in the research)!

P.S.

doi: 10.1177/0885328220970756

This could be interesting (it is new for me, I do not know the properties, and it is potentially for medical application; however, the composition is promising (for Ti 20%)).

1. the direction of the dislocation line should be non f boundary condition. I use p in that direction.

2. should be zero not null because null will do a time integration for that direction, which is un-necessary.

3. fix 5 should be on middle atoms.

plus: you are missing one thermal layer (typically, fixed layer, thermal layer and mobile layer) if you use this model.

Hi,

The starting point is to understand the behaviour of your metal in the corrosive environment. Next is identifying the appropriate circuit (one or two time constant) in zimswipin software based on the nature of your data. Furthermore, to compare the accuracy of the selected circuit, please the the chi square value and the corresponding Rct values.

The maximum silicon (Si) content in aluminum-silicon (Al-Si) alloys can vary depending on the specific alloy composition and application. However, one of the commonly used Al-Si alloy series is the 3xx.x series, which typically contains silicon in the range of 1-20%. For example:

Higher silicon content can be found in specialized alloys, such as some of the 4xx.x series and 6xx.x series, which may contain silicon ranging from 4-20% or more.

Regarding the parting limit during dealloying or chemical leaching of Al-Si alloys, the extent of dealloying is influenced by various factors including the alloy composition, microstructure, processing conditions, and the specific dealloying method employed. There is no universally fixed "parting limit" as it depends on these aforementioned factors.

Dealloying involves selectively dissolving one component (often less noble) from an alloy leaving behind a porous structure enriched in the more noble component. During dealloying of Al-Si alloys, silicon is typically less noble than aluminum, so the silicon tends to dissolve more readily.

The extent of dealloying or the parting limit can vary based on the conditions of the dealloying process, the specific alloy composition, and the desired final structure. Detailed studies and experiments would be needed to determine the precise parting limit for a particular Al-Si alloy under specific dealloying conditions. It's important to consider the purpose of the dealloying and tailor the process to achieve the desired properties and structure in the remaining material after dealloying.

Thank you for your response Mr. , I have some limitations with trying out other methods of indentation.

for detail go through this paper

To calculate the mixing enthalpy of any HEA alloy using molar fraction, atomic radius, and electronegativity, the following steps can be followed:

Average atomic radius = (x1 * r1 + x2 * r2 + x3 * r3 + ... + xn * rn) / (x1 + x2 + x3 + ... + xn) Average electronegativity = (x1 * e1 + x2 * e2 + x3 * e3 + ... + xn * en) / (x1 + x2 + x3 + ... + xn)

where:

Mixing enthalpy = AHmix = (x1 * H1 + x2 * H2 + x3 * H3 + ... + xn * Hn) + (x1 * x2 * ΔHmix12 + x1 * x3 * ΔHmix13 + ... + xn * xn-1 * ΔHmixn-1n)

where:

The enthalpies of mixing of the pure elements and the binary pairs of elements can be found in the literature.

It is important to note that the above equation is only an approximation of the mixing enthalpy of HEA alloys. The actual mixing enthalpy of a HEA alloy can be more complex due to factors such as the formation of intermetallic compounds and short-range order.

Here is an example of how to calculate the mixing enthalpy of a HEA alloy using the above steps:

Example: Calculate the mixing enthalpy of a HEA alloy with the following composition:

Average atomic radius = (0.30 * 1.25 + 0.30 * 1.25 + 0.20 * 1.28 + 0.20 * 1.24) / (0.30 + 0.30 + 0.20 + 0.20) = 1.26 Å Average electronegativity = (0.30 * 1.61 + 0.30 * 1.88 + 0.20 * 1.66 + 0.20 * 1.91) / (0.30 + 0.30 + 0.20 + 0.20) = 1.76

Mixing enthalpy = AHmix = (0.30 * HAl + 0.30 * HCo + 0.20 * HCr + 0.20 * HNi) + (0.30 * 0.30 * ΔHmixAlCo + 0.30 * 0.20 * ΔHmixAlCr + 0.30 * 0.20 * ΔHmixAlNi + 0.20 * 0.20 * ΔHmixCoCr + 0.20 * 0.20 * ΔHmixCoNi + 0.20 * 0.20 * ΔHmixCrNi)

The enthalpies of mixing of the pure elements and the binary pairs of elements can be found in the literature. For example, the enthalpy of mixing of Al and Co is -1.7 kJ/mol.

Assuming that the enthalpies of mixing of the other binary pairs of elements are also negative, the overall mixing enthalpy of the HEA alloy will be negative. This indicates that the HEA alloy is more stable than a mixture of the pure elements.

It is important to note that the above calculation is only an approximation of the mixing enthalpy of the HEA alloy

Here are some references for the information in my previous answer:

These references provide a more detailed overview of the theory and practice of calculating the mixing enthalpy of HEA alloys.

Additionally, here are some links to online resources that contain information on the enthalpies of mixing of pure elements and binary pairs of elements:

I hope this is helpful.

Addenda

I searched the web for some possible methods to calculate the mixing enthalpy of any HEA alloy and found the following information:

ΔHmix​=∑ ∑ xi​xj​ΔHij​ from i=1 to n and from j=1 to n

where n is the number of elements, xi​ and xj​ are the molar fractions of elements i and j, and ΔHij​ is the pairwise mixing enthalpy between elements i and j, which can be calculated from their electronegativity and atomic radius values using empirical formulas[2].

where Gex​ is the excess Gibbs energy, T is the temperature, and P is the pressure.

I hope this helps you with your question.

Good luck

Thank Sumit Bhowmick for the detailed answer.

One possible method of determining the enthalpy of mixing between two elements theoretically is to use the regular solution model, which assumes that the atoms are randomly distributed and that the enthalpy of mixing depends on the difference in the atomic sizes and the bond energies of the elements. The regular solution model can be expressed as follows:

ΔH mix = zNε(1 - x)x

where ΔH mix is the enthalpy of mixing per mole of solution, z is the coordination number, N is the Avogadro’s number, ε is the interaction energy between unlike atoms, and x is the mole fraction of one of the elements.

The interaction energy ε can be estimated from the bond energies of the pure elements using the following formula:

ε = (E A + E B )/2 - E AB

where E A and E B are the bond energies of the pure elements A and B, and E AB is the bond energy of the compound AB.

The bond energies can be obtained from experimental data or calculated from theoretical methods, such as density functional theory or molecular dynamics.

For more details and examples of this method, you can refer to these sources:

Enthalpy of Mixing in Binary Alloys: A Simple Model

Thermodynamic Modeling of Alloys

there are other possible methods to determine the enthalpy of mixing between two elements theoretically. Some of them are:

These are some examples of alternative methods to calculate the enthalpy of mixing theoretically. However, each method has its own assumptions, limitations, and parameters that need to be determined or fitted from experimental data or first-principles calculations. Therefore, no single method can be universally applicable or accurate for all kinds of solutions.

Here is a summary of the methods:

ΔH mix = zNε(1 - x)x

where ΔH mix is the enthalpy of mixing per mole of solution, z is the coordination number, N is the Avogadro’s number, ε is the interaction energy between unlike atoms, and x is the mole fraction of one of the elements.

The source for this method is Lecture 3: Models of Solutions - University of Cambridge.

ΔH mix = zNε(1 - x)x + zNβ(1 - x)x(1 - 2x)

where ΔH mix is the enthalpy of mixing per mole of solution, z is the coordination number, N is the Avogadro’s number, ε is the average interaction energy between unlike atoms, β is a parameter that measures the deviation from regularity, and x is the mole fraction of one of the elements.

The source for this method is Lecture 7: Quasichemical Solution Models - University of Cambridge.

ΔH mix = −zN(NA2AA + NB2BB − NABω)

where ΔH mix is the enthalpy of mixing per mole of solution, z is the coordination number, N is the Avogadro’s number, NA , NB , and NAB are the numbers of AA , BB , and AB bonds per atom, respectively, and ω = 2AA + 2BB − 22AB is a parameter that measures the bond energy difference between like and unlike atoms.

The source for this method is Cluster Variation Method Analysis of Correlations and … - Springer.

ΔH mix = −zN(NA2AA + NB2BB − NABω) − zN(NABCωABC + NABDωABD + …)

where ΔH mix is the enthalpy of mixing per mole of solution, z is the coordination number, N is the Avogadro’s number, NA , NB , NAB , NABC , NABD , etc. are the numbers of AA , BB , AB , ABC , ABD , etc. clusters per atom, respectively, ω = 2AA + 2BB − 22AB is a parameter that measures the bond energy difference between like and unlike atoms, and ωABC , ωABD , etc. are parameters that measure the cluster interaction energies.

The source for this method is Cluster Variation Method | SpringerLink.

good luck

I found there is available HEA database in the version 2023 Thermocalc Software.

Thank you for this answer Sumit Bhowmick it must certainly be copper phosphate. i thought that it needed much harsher condition to oxidize but maybe not.

thank you again

sincerely

Zakaria

Dear Nidhi Chaubey

The square notch you mentioned might be providing a stress concentration that leads to accelerated crack propagation. If the square notch geometry creates a more severe stress concentration compared to other notch shapes, the crack might propagate more rapidly.

Sai Vamsi Krishna Tataverthi

Yes, W-H plot is used to calculate lattice strain and crystallite size specifically for crystalline materials. As cast alloys are relatively more crystalline in nature. So, W-H can be used to to calculate lattice strain and crystallite size for as-cast alloys.

If you're using an aqueous electrolyte, then starting with a beaker cell probably makes the most sense (after a thorough chemical risk assessment). Although I can't comment on the best setup for your plating/stripping experiment, the conventional tests (CV, GCD and EIS) can all be done with a beaker cell. As for the number of electrodes, that is dependent on the goal of your test; CV is much more reliable with a third (reference) electrode while I would recommend starting EIS with a third (reference) electrode until the expected values and time for equilibrium are better known. To switch to 2-electrode tests such as for GCD, simply piggyback the wire labelled counter electrode (CE) to the one labelled reference electrode (RE) from your equipment. I explain in more detail about this here:

Hi Amit Kumar Singh Chauhan,

You're correct that peak broadening in X-ray diffraction (XRD) can result from various factors, including solid solution effects, lattice strain, and crystallite size. While peak broadening can arise from multiple sources, the Williamson-Hall method provides a way to approximate the average crystallite size. This is because it doesn't require specialized equipment or extensive sample preparation, making it suitable for evaluating microstructural features in various materials. The method van also be used for comparative studies, where changes in crystallite size due to different processing conditions or heat treatments can be tracked, even if other factors like strain are present.

While , they might require more complex analyses and additional data.

For more detailed insights into specific microstructural features, more advanced methods could potentially separate the different contributions more accurately using techniques, such as transmission electron microscopy (TEM) or electron backscatter diffraction (EBSD) might be more appropriate.

Hope this helps,

Kind regards

hello

did you try reagent:

20ml HNO3+60ml HCl, immerse or swab 5-60s.

or electrolytic at 6V: 10g oxalic acid+100ml H2O, 2-3s. use stainless steel cathode and platinum or nichrome connection to specimen

good luck.

Carlos Ariel Samudio Pérez Understood, thankyou. How to get the phase graph when we alloying the elements?

Hi Ashwani Kushwaha I think the best way so far to handle the DFT calculation with quantum espresso, is to perform it via Materialssquare platform. You even can create your structure there easily and connect it to the QE module where the suitable Pseudopotential for each element in your structure will be selected for you in easy and soft way. This here the site https://www.materialssquare.com/work and you can also see this video how to do the DFT in general with materialssquare for example here https://www.youtube.com/watch?v=7V2eQkNxKdo. Once done you can still able to download and extract your input structure easily if you don't want to run your DFT on cloud servers.

Could you send the X-Y ascii format, so that let me try.

Dear Dr. 圭圭 Li ,

I suggest you to have a look at the following, interesting document:

Corrosion of Copper Alloys in Consumer Electronics Environments

Anand V. Samant And Fritz C. Grensing

NACE INTERNATIONAL: VOL. 54, NO. 12

Available at: https://materion.com/-/media/files/alloy/article-reprints/materials-performance-dec15_pp-64-67.pdf

where Standard ASTM Methods were used and cited in Bibliography.

My best regards, Pierluigi Traverso.

In Binder Jet 3D Printing (BJP), cobalt-based alloys are often combined with a specific type of binder material to create the printed parts. The binder serves as the adhesive that binds the metal powder particles together to form the green part, which is a fragile, porous, and non-sintered 3D printed object. After printing, the green part undergoes post-processing steps, including debinding and sintering, to achieve the final dense metal part.

For cobalt-based alloys in Binder Jet 3D Printing, the common binders used are:

The choice of binder depends on various factors, including the specific cobalt-based alloy used, the 3D printing equipment, the required part properties, and the intended post-processing methods. Different binders may have distinct effects on the green part's mechanical properties, dimensional accuracy, and ease of debinding.

After the printing process, the green part is subjected to a debinding process, where the majority of the binder is removed to create a porous structure. The final step is sintering, where the part is heated to high temperatures to fuse the metal particles together, resulting in a fully dense and functional metal component.

It's important to note that different 3D printing systems and material formulations may use variations of binders to achieve optimal results for cobalt-based alloy parts. Always follow the manufacturer's guidelines and recommended materials for your specific Binder Jet 3D Printing system and application.

In binder jet 3D printing, the choice of binder is very crucial. It is a complex problem that depends on various factors like the powder's material, the final part's required properties, post-processing steps, and safety and environmental considerations.

For metallic powders such as copper alloys, typically, the binders used are based on acrylic or polyvinyl alcohol (PVA) materials. These are often preferred due to their good binding properties and relatively easy burnout during the post-processing phase.

Here are a few types of binders you could consider:

While these binders can provide good binding for copper alloy powders, it's important to note that the choice of binder is only one aspect of the process. The binder content, printing parameters, and post-processing steps (like debinding and sintering) all play a significant role in determining the density and mechanical properties of the final part. Therefore, optimising all these parameters for your specific application may take some trial and error.

Also, remember always to consider safety and environmental impacts when choosing a binder. Many binders can release harmful gases during burnout, so proper ventilation and safety measures are important.

Finally, it's also beneficial to consult with binder manufacturers or experts in binder jetting, as they may be able to provide more specific recommendations based on their experience and your particular needs.