Ruifeng Zhang

Ruifeng Zhang
Central South University | CSU ·  School of Materials Science and Engineering

PhD

About

45
Publications
11,003
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843
Citations
Citations since 2017
36 Research Items
723 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200

Publications

Publications (45)
Article
Full-text available
Localised corrosion of the aluminium alloy AA5083-H111 in a simulated dynamic seawater/air interfacial zone and a full seawater immersion zone was investigated with electrochemical impedance spectroscopy and electrochemical noise. Al-Fe/Ti intermetallic particles (IMPs) on localised corrosion were examined with focused ion beam, transmission electr...
Article
In this work, we presented an investigation into the deformation behavior of laser powder bed fusion (LPBF) Ti-6Al-4V (Ti64), particularly how microstructure characteristics determined the grain deformation behavior by using in-situ SEM tensile characterization. Results demonstrated that α laths with their elongation directions 45° to the tensile l...
Article
Heat treatment (HT) is an effective way to attain the desired microstructure and mechanical properties in laser powder bed fusion (LPBF) Ti–6.5Al–2Zr–1Mo–1V (TA15). However, previous studies only obtained the high tensile ductility of LPBF TA15 but were accompanied by a large loss of strength, which was unable to achieve balanced mechanical propert...
Article
Hot processing maps have been widely used to reveal the relationship between microstructures and final performances of Al–Li alloys after deformation. However, there are few researches on the hot processing maps of 1460 Al–Li alloy. In this paper, the safe zones were identified based on the corrected data with temperatures range from 300 to 500 °C...
Article
Full-text available
The recently-developed Al-Mn-Sc based alloys fabricated by laser-powder bed fusion (L-PBF) have achieved a yield strength of 560 MPa and a ductility of 18%. However, these high strength Al alloys normally exhibit severely non-uniform plasticity due to the strain incompatibility of bimodal grain structure, which hinders their practical application....
Article
The defects remain a significant issue for additive manufactured titanium alloys, which hinders their further market penetration. In this work, we proposed a new understanding of the inhomogeneous microstructure formation affected by defects with detailed EBSD characterization, and how the defects and inhomogeneous microstructures determined the st...
Article
Full-text available
The effects of pre‐deformation to higher levels on mechanical properties, strengthening contribution, and microstructures of 2A55 Al‐Li alloy were investigated. Results show that the tensile strength of 2A55 Al‐Li alloy approaches 660 MPa with an elongation of 9.28% after 15% pre‐deformation. The strengthening contribution from precipitates and str...
Article
Dynamic precipitation and recrystallization behavior during middle-temperature and appropriate strain rates provide a chance to obtain desirable structure, which significantly improve the mechanical properties of aluminum alloys. In this paper, the microstructure evolution in the typical regions of processing map of 2195 Al-Cu-Li alloy during hot c...
Article
Al-5.8Mg-0.4 Mn with minor alloying additions of Sc and Zr was investigated via electrochemical testing and nitric acid mass loss testing (NAMLT) in order to reveal the influence of Sc and Zr upon sensitization and intergranular corrosion. The Al-Mg-Mn alloys were also analysed using an electron probe microanalyzer, indicating that β-phase (Mg2Al3)...
Article
Full-text available
To study the effects of dynamic precipitation and processing parameters on the dynamic recrystallization (DRX) behavior of 2195 Al-Cu-Li alloy, the hot deformation process was investigated comprehensively with the temperature range of 300-500°C and strain rate range of 0.001-10 s-1. An Arrhenius-type constitutive equation and DRX kinetics model wer...
Article
Full-text available
The unique thermal history of selective laser melting (SLM) can lead to high residual stress and a non-equilibrium state in as-fabricated titanium alloy components and hinders their extensive use. Post heat treatment, as a classical and effective way, could transform non-equilibrium α’ martensite and achieves desirable mechanical performance in SLM...
Article
The processability and final mechanical properties of AlLi alloys are strongly affected by the uniformity of solute element and the degree of recrystallization, which can be improved via homogenization treatments. It is essential to control the microstructure to achieve the desired properties. In this work, the optimal double-step homogenization (D...
Article
The quench sensitivity of 2050 Al-Cu-Li alloy was determined by the time-temperature-transformation (TTT) curves and time-temperature-property (TTP) curves based on conductivity and hardness. Additionally, a novel end quenching test was used to investigate the quench sensitivity of cold-rolled sheets with a thickness of 2 mm which cannot be tested...
Article
Full-text available
The effect of microstructure evolution on the tensile properties of 2050 Al−Li alloy thick plate aged at 150 °C with 80 mm in thickness (t) was studied from a microstructural perspective. Scanning electron microscope, optical microscope, transmission electron microscope and X-ray diffractometer were used to explore the surface (t/6), interlayer (t/...
Article
The quench sensitivity and time-temperature-transformation (TTT) curves/time-temperature-property (TTP) curves of the 2060 Al-Cu-Li alloy with a 0.68 wt% Mg content was investigated by the quench-ending method and the interrupted quench technique. It was found that the quenching depth of the studied alloy was approximately 24 mm. The nose temperatu...
Article
Full-text available
The influence of different Mg concentrations on the mechanical properties and microstructure of an Al-Li alloy was studied. The highest Mg content was up to 1.1 wt.%. To the best of the authors knowledge, alloys with such a high Mg content has not been reported in the literature. The mechanical properties, yield strength and elongation at failure,...
Article
Mechanical properties, precipitate microstructures and textures of AA 2195 Al-Cu-Li alloy with different rolling schedules and subsequent artificial ageing heat treatment have been investigated. The highest ultimate tensile strength (UTS) and yield strength (YS) were obtained in longitudinal direction of the hot-rolled alloy at 280℃ due to a higher...
Article
The hemming process is one of the most commonly used forming processes for aluminium alloys in the automotive industry and requires bending the aluminium alloy sheet to 180° without generating cracks or surface cosmetic defects. However, existing commercial Al-Mg-Si alloys (AA6xxx aluminium alloys) used in the automotive industry could easily fail...
Article
Full-text available
The influence of Ag on the microstructure evolution of an aged Al–Cu–Li–Mg alloy was studied. The coarse Cu-rich precipitates containing Ag and Mg were found during the whole ageing process of Al–Cu–Li–Mg–Ag alloy. Besides, Ag addition in the Al–Cu–Li–Mg alloy accelerates the hardness value reduction of the overaged alloy. When the alloy was over h...
Article
Full-text available
Transmission electron microscope and selected area electron diffraction were employed to characterize the precipitates in 2A97 Al–Li alloy with 1.5 wt% Li concentration, which were aged at 150 °C (with 6% pre-deformation) and 165 °C (without pre-deformation) for various time. The diameter of the plate-like T1, δ′/GP/δ′ and δ′/θ'/δ′ precipitates wer...
Article
The evolution of precipitate microstructures of the Al-1.0wt%Cu-2.5wt%Li alloys with different micro-alloyed elements addition was investigated during ageing at 175 °C together with the mechanical properties and corrosion resistance. It was found that the Al-Cu-Li alloy with Zn addition possesses not only higher yield strength but also improved int...
Article
The microstructure evolution and the corrosion feature of Al–xCu–yLi–Mg alloys (x:y = 0.44, 1.65 and 4.2) were systematically investigated under the same artificial aging conditions. The relationships between types of precipitates and mechanical performance, as well as electrochemical behaviors, were discussed. Our results show that different types...
Article
Full-text available
The tensile properties and corrosion behaviours of an ageing Al-1.7 Cu-4.0 Li- 0.4 Mg alloys (in at. %) with or without 0.3 Zn addition were investigated by detailed microstructure evolution using TEM and STEM. Herein, the Zn addition to the Al-1.7 Cu-4.0 Li- 0.4 Mg ageing alloy is determined as a convincing approach to optimising the strength-corr...
Article
The corrosion behavior of the 1445 aged alloy was studied by analysis of microstructure characteristics and grain structure characteristics achieved from TEM, STEM, and EBSD. Three corrosion modes including intergranular corrosion (IGC), sub-intergranular corrosion (SIGC), and sub-intragranular corrosion (SGC) were found in the aged samples. In con...
Article
To develop biodegradable magnesium alloy with desirable corrosion properties, a low Gd-containing Mg–3Gd–1Zn–0.4Zr (wt%, GZ31K) alloy was prepared. The as-cast ingot was solution treated and then hot extruded. Microstructures were characterized by scanning electron microscopy (SEM). Corrosion behavior of the alloy under each condition was studied b...
Article
The 5xxx series aluminium alloys are susceptible to sensitisation during service at elevated temperatures. Sensitisation refers to deleterious grain boundary precipitation resulting in rapid intergranular corrosion in moist environments. A holistic understanding of the variables that can influence the degree of sensitisation in Al-Mg-Mn alloys is p...
Article
Strontium phosphate (SrPO 4 ) conversion coatings with the ability to impart significant corrosion resistance were prepared upon magnesium alloy Mg-3Al-4.3Ca-0.1 Mn (wt.%). Scanning electron microscopy equipped with energy dispersive spectroscopy and transmission electron microscopy were also employed to characterise surface and interfacial morphol...
Article
The influence of various amounts of Zn addition on the microstructure and associated intergranular corrosion of Al-2.8Cu-1.7Li-0.4Mg-0.3Mn-0.12Zr alloys was studied using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, and corrosion and electrochemical techniques. The added Zn was incorporated into the precipitat...
Article
The IGC behaviour, OCP and microstructure of AA1460 (Al-3.12Cu-2.14Li-0.12Sc-0.12Zr, in wt.%), following HT1 (heat treatment without predeformation) and HT2 (heat treatment with predeformation) tempers were investigated. Both δ′ (Al 3 Li) and T 1 (Al 2 CuLi) phases were precipitated within grains during heat treatment, while T 1 phase also precipit...
Article
Full-text available
The influences of annealing prior to solution treatment on the grain structure, subsequent aging precipitates, and intergranular corrosion (IGC) of Al-Cu-Li alloy (AA2050) sheet with T6 aging at 448 K (175 °C) were investigated. Annealing impedes the full recrystallization during solution treatment, increasing the population density of T1 (Al2CuLi)...
Article
The present paper reports a quasi-in-situ STEM-EDS approach for studying the role of Ag in the corrosion behaviour of Mg-Gd-Zr alloys. Following corrosion, the segregation of O at the interface of the α-Mg matrix and the β phase was observed. Furthermore, Ag-rich particles and the re-deposition of Ag were also observed on the nanoscale. Based on qu...
Article
The intergranular corrosion of Al-Mg alloys arises from sensitisation due to thermal exposure. Here, a protected low angle (8.7°) grain boundary which hinders the intergranular corrosion propagation in a sensitised (150°/7 d) Al-Mg alloy was studied in detail. Discrete β-phase was observed on this protected boundary, but with a lower continuity com...
Article
Full-text available
An empirical model for the evolution of β-phase (Mg2Al3) along grain boundaries in aluminium alloy AA5083 (Al-Mg-Mn) during isothermal exposures is proposed herein. Developing a quantitative understanding of grain boundary precipitation is important to interpreting intergranular corrosion and stress corrosion cracking in this alloy system. To date,...
Article
Full-text available
The 5xxx series (Al-Mg-based) aluminum alloys suffer from intergranular corrosion and intergranular stress corrosion cracking when the alloy has become "sensitized." Sensitization refers to insidious precipitation of beta phase (Mg2Al3), which is problematic when present at grain boundaries. The beta phase is electrochemically active and may prefer...
Article
Full-text available
AA5083 specimens (with a nominal composition of Al-4.4Mg-0.5Mn) from the same original plate were prepared with a variation in grain size imparted by cold rolling, cryo rolling, equal channel angular pressing and high-pressure torsion. Electron backscatter diffraction was used to determine the grain size and misorientation. The effect of grain size...
Article
This paper presents a hypothesis and its experimental validation that simultaneous improvement in the hardness and corrosion resistance of aluminum can be achieved by the combination of suitable processing route and alloying additions. More specifically, the corrosion resistance and hardness of Al-xCr (x = 0-10 wt.%) alloys as produced via high-ene...
Article
A range of alloys based on the Al-4Mg-0.4Mn system were produced with selected quaternary microalloying additions. In Part 1 of this study, the electrochemical and corrosion response was studied. To characterise the sensitisation behaviour of these alloys, where sensitisation is the major mode of degradation of 5xxx alloys, heat treatment at 150°C...
Article
Full-text available
The calculated effect of a range of quaternary alloying additions to aluminium alloy AA5083 (Al-4.4Mg-0.5Mn) was investigated. Attention was given to influence of composition on the volume fraction of β-phase (Mg2Al3), and the possible formation of any additional phases (which we term γ-phase herein). Alloying additions of silver, cerium, copper, l...
Article
The influence of Mg content on the degree of sensitization (DoS) of Al-xMg-0.5Mn (wt%) alloys (where x varies from 3.36 wt% to 8.85 wt%) was investigated via the nitric acid mass loss test (NAMLT). NAMLT upon sensitized specimens revealed that mass loss was negligible below ∼4.01 wt% Mg, while for Mg content ≥4.01 wt%, mass loss increased monotonic...
Article
The influence of neodymium (Nd) additions from 0 to 0.17 wt.% on the electrochemical response, corrosion, and hardness of a model 5xxx alloy (Al–5Mg) was studied. The combination of SEM, polarisation, constant immersion and nitric acid mass loss testing, followed by optical profilometry, revealed that Nd had no significant effect on pitting or gene...
Article
Full-text available
Sensitization of 5xxx series Al alloys involving precipitation of beta phase (Mg2Al3) at grain boundaries was studied for different exposure times at 100 degrees C upon AA5083-H131 (UNS A95083). In this work, we reveal that fracture surfaces prepared by liquid gallium embrittlement can yield a quantification of grain boundary beta phase with signif...
Article
Low-level Nd additions, up to 0.17 wt%, were added to Al-5Mg to explore the impact on the subsequent degree of sensitization. Following heat treatment at 150 degrees C for 1 day and 7 days, nitric acid mass loss (NAMLT) tests revealed that additions of >0.11% Nd were effective at decreasing the amount of subsequent intergranular attack.

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