Narendra B. Dahotre

Narendra B. Dahotre
University of North Texas | UNT · Department of Materials Science and Engineering

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343
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Publications

Publications (343)
Article
Full-text available
In this work, we report a non-destructive and non-contacting ultrasound system with a novel air-coupled transducer to continuously monitor the drying process of prickly pear (nopal) pads in a lab environment. Compared with conventional imaging and spectroscopic methods or electrical-based approaches, ultrasound-based methods are non-invasive, cost-...
Preprint
This study proposes a new data-driven approach to predict the area fraction of lack of fusion and morphology of 3D-printed parts produced using the laser powder bed fusion process. Different processing parameters were considered to develop this methodology, such as laser power, laser speed, hatch spacing, and layer thickness. Melt pool geometrical...
Article
Full-text available
The primary bottlenecks faced by the laser powder bed fusion (LPBF) process is the identification of optimal process parameters to obtain high density (> 99.8%) and a good surface finish (< 10 µm) in the fabricated components. Prediction of optimal process maps with the help of machine learning (ML) models is still challenging due to extensive trai...
Article
Full-text available
Current work explored solid-state additive manufacturing of AZ31B-Mg alloy using additive friction stir deposition. Samples with relative densities ≥ 99.4% were additively produced. Spatial and temporal evolution of temperature during additive friction stir deposition was predicted using multi-layer computational process model. Microstructural evol...
Article
We designed and characterized a 3D printed acoustic shear wave polarization rotator (PR) based on the specific nature of the fused-deposition-modeling printing process. The principle of the PR is based on rotation of the polarization axis of a shear wave due to the gradual change in orientation of the axis of anisotropy along the direction of wave...
Article
The present work investigated additive manufacturing of CoCrMo alloy via laser‐based directed energy deposition process. A range of five different laser powers were used for the fabrication of fully dense and metallurgically sound CoCrMo samples. The solidification parameters including temperature gradient, growth rate, and the cooling rate were co...
Article
The current work explored additive friction stir deposition of AZ31B magnesium alloy with the aid of MELD® technology. AZ31B magnesium bar stock was fed through a hollow friction stir tool rotating at constant velocity of 400 rpm and translating at linear velocity varied from 4.2 to 6.3 mm/s. A single wall consisting of five layers with each layer...
Article
Complex thermokinetics associated with laser‐based powder bed fusion additive manufacturing of Titanium alloy component resulted in evolution of nearly non‐equilibrium metastable microstructures and spatially variable aqueous electrochemical response. Further details can be found in the article number 2100938 by Narendra B. Dahotre and co‐workers.
Article
Full-text available
The industrial Internet of Things (IIoT) has grown to empower advantages of advanced manufacturing machinery and smarter control. The cloud-based technology of remote data collection, intelligent machine interconnectivity, and sensor monitoring provide the opportunity for a pattern modification across all manufacturing divisions including the lates...
Article
The current study investigated evolution of fine-scale microstructure in H13 steel additively manufactured by laser directed energy deposition. X-ray diffraction, scanning electron microscopy, and site specific transmission electron microscopy were employed for the analysis. A multiphysics, multi-layer, and multi-track computational process model i...
Article
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The effect of non-isothermal treatment in oxygen-containing air, via heating rates of 10, 50, and 1000 °C/min until 1000 °C followed by furnace cooling to room temperature on oxides formed on directed laser energy additively fabricated IN718 was studied. Another set of samples heated up to 1000 °C using the same heating rates were isothermally held...
Article
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This study presents novel in-situ monitoring of the melting pool behavior and ex-situ inspection of the heat-affected softening in gallium metal using an ultrasonic technique. In the laser welding and laser melting additive manufacturing process, understanding the melting pool's behavior is necessary but challenging. Optical, thermal, and radiation...
Article
Titanium (Ti)-based alloys wield unique combination of mechanical, chemical, and high temperature properties, which place them at the forefront of engineering applications ranging from biomedical to aerospace. Among these properties, electrochemical and thermal-induced degradation involving corrosion and high-temperature oxidation, respectively, ar...
Article
The present work investigates the spatial variation in electrochemical behavior of laser powder bed fusion (LPBF) fabricated Ti6Al4V alloy. The electrochemical behavior of LPBF-printed Ti6Al4V was measured using potentiodynamic polarization and electrochemical impedance spectroscopy at different regions along the build direction. The varying kineti...
Article
Full-text available
Additive manufacturing technologies based on metal are evolving into an essential advanced manufacturing tool for constructing prototypes and parts that can lead to complex structures, dissimilar metal-based structures that cannot be constructed using conventional metallurgical techniques. Unlike traditional manufacturing processes, the metal AM pr...
Article
The current work investigated additive manufacturing of H13 steel via laser aided directed energy deposition (L-DED) technique. The laser power was kept constant at 350 W, whereas, the laser beam speed was varied in the range of 5.8–14.8 mm/s (laser fluence: 77–30 J/mm2). Cube samples of dimensions 2.5 × 2.5 × 2.5 cm3 were additively manufactured....
Article
Laser engineered net shaping (LENS) processing of an in-situ Ti-B4C composite, results in the natural formation of a novel periodically layered structure, when a mixture of Ti powders and B4C powders are used as a feedstock. One of the layers predominantly consisted of TiB2 and inter-dendritic TiC phases, while the other alternating layer exhibited...
Article
Cryogenic thermal cycling was done for the rejuvenation of Cu46Zr47Al7 and Cu45Zr47Al7Ti1 amorphous alloys. The effect of rejuvenation on the tribological behavior of these two amorphous alloys was investigated against Si3N4 ball by reciprocating sliding wear test. A significant improvement in the tribological properties was seen for the rejuvenate...
Article
Full-text available
Submerged steel pipes are susceptible to corrosion due to long exposure under harsh corrosive conditions. Here, we investigated the reliability and effectiveness of nonwoven zinc(II) oxide-polyvinylidene fluoride (ZnO-PVDF) nanocomposite fiber textiles as an embedded corrosion sensor. An accelerated thermal cyclic method paired to electrochemical i...
Article
The high strength metastable β-Ti alloy, Ti–1Al–8V–5Fe (wt%), also referred to as Ti-185, has been successfully processed using the directed energy deposition (DED) based laser engineered net shaping (LENS) process, obviating the beta fleck problem associated with Fe micro-segregation that has been reported in conventionally processed counterparts....
Article
Generation of inherently complex thermokinetics and thermomechanical conditions during the laser powder bed fusion-based additive manufacturing (LPBF-AM) process makes it challenging to understand the evolution of internally twinned martensite structure in Ti6Al4V. In view of this, the present study employed the finite element method based multiphy...
Article
The laser-engineered net-shaping (LENSTM) process was employed for directed energy deposition (DED) of Ti-35Nb-7Zr-5Ta (wt.%) or TNZT, a low modulus metastable β-Ti alloy for biomedical applications. The laser power was varied in the range of 400–600 W, while keeping all other parameters constant. A change in the overall grain morphology was noted...
Article
The spatial variation of thermokinetic parameters has a significant influence on solidification and microstructural aspects such as grain orientation, types and dimensions of the microstructural features, and crystallographic defects. In laser-based additive manufacturing, these factors are mainly dependent on the process parameters and have a wide...
Article
This paper reports the dynamic elastic constants of laser powder bed fusion additively manufactured Ti6Al4V alloy by recently developed effective bulk modulus elastography technique and compares them with the static elastic constants evaluated using the nanoindentation technique. With this elastography technique, two ultrasound frequencies (10 MHz...
Article
Full-text available
Laser surface engineering has been employed to mimic the microstructural evolution during laser-based additive manufacturing of Alloy 718, specifically when the layers are successively fused and solidified. The micro-segregation of alloying elements in the fusion zone of laser surface melted Alloy 718 samples has been found to have a strong influen...
Article
Full-text available
The current work explores the surface morphology of the laser-ablated bone using Yb-fiber coupled Nd:YAG laser (λ = 1064 nm) in continuous wave mode. As the laser-ablated region contains physiochemically modified carbonized and nonstructural region, it becomes unknown material for the body. Thus, biomineralization on such a laser-ablated region was...
Article
Full-text available
The present work explored effects of laser surface melting on microstructure and surface topography evolution in AZ31B magnesium alloy. Thermokinetic effects experienced by the material during laser surface melting were simulated using a multiphysics finite element model. Microstructure and phase evolution were examined using scanning electron micr...
Article
Full-text available
Rapid thermokinetics associated with laser-based additive manufacturing produces strong bulk crystallographic texture in the printed component. The present study identifies such a bulk texture effect on elastic anisotropy in laser powder bed fused Ti6Al4V by employing an effective bulk modulus elastography technique coupled with ultrasound shear wa...
Article
In this study, a novel acoustic doublet meta-material lens has been designed and tested to demonstrate both far-field focal point and ultra-long collimation characteristics past the Fresnel zone. The switching of the two behaviors can be adjusted by simply linear mechanical motion of one of the lens units. The doublet lens is able to focus the soun...
Article
Full-text available
The advent of 3D digital printers has led to the evolution of realistic anatomical organ shaped structures that are being currently used as experimental models for rehearsing and preparing complex surgical procedures by clinicians. However, the actual material properties are still far from being ideal, which necessitates the need to develop new mat...
Article
While BCC Fe-Co alloys form an important class of soft magnetic alloys, they are often challenging to process in near net shape, due to the formation of the hard embrittling ordered B2 phase. Additive manufacturing (AM) technologies, such as laser engineered net shaping (LENS), permit processing these alloys in complex near-net shapes while control...
Article
Full-text available
The electrochemical response of laser powder bed additively manufactured Ti6Al4V is often considered at room-temperature conditions; however, structural Ti6Al4V components in a warm marine environment tend to respond differently. In light of this, the present work investigates the electrochemical response of the Ti6Al4V fabricated using laser powde...
Article
Full-text available
The extensive research on the laser machining of the bone has been, so far, restricted to drilling and cutting that is one- and two-dimensional machining, respectively. In addition, the surface morphology of the laser machined region has rarely been explored in detail. In view of this, the current work employed three-dimensional laser machining of...
Article
Full-text available
In this study, a novel ultrasonic non-destructive and non-invasive elastography method was introduced and demonstrated to evaluate the mechanical properties of fused deposition modeling 3D printed objects using two-dimensional dynamical elasticity mapping. Based on the recently investigated dynamic bulk modulus and effective density imaging techniq...
Article
Direct laser deposition of a mixture of titanium (Ti) and boron-carbide (B4C), using the laser engineered net shaping process, results in a complex multi-phase Ti matrix composite due to the incipient interfacial reactions between liquid titanium and solid/partially melted B4C. Detailed microstructural characterization, at multiple length scales, r...
Article
Full-text available
The present study aims to evaluate effect of hydroxyapatite (HA, Ca10(PO4)6OH2), a ceramic similar to natural bone, into AZ31B Mg alloy matrix on biomineralization and biocompatibility. The novel friction stir processing additive manufacturing route was employed to fabricate Mg-HA composites. Various HA contents (5, 10, 20 wt%) were incorporated in...
Article
Full-text available
This paper reports the computational approach adopted for thermo-diffusion kinetics to rationalize homogenously distributed nanoscale vanadium-rich clusters formed within the martensite laths of Ti6Al4V alloy printed using laser powder bed fusion at an energy density of 52.08J/mm3. The computations were conducted using a finite element method based...
Article
Full-text available
Corrosion in underground and submerged steel pipes is a global problem. Coatings serve as an impermeable barrier or a sacrificial element to the transport of corrosive fluids. When this barrier fails, corrosion in the metal initiates. There is a critical need for sensors at the metal/coating interface as an early alert system. Current options utili...
Article
Full-text available
Although most of the near non-equilibrium microstructures of alloys produced by laser powder bed fusion (LPBF) additive manufacturing (AM) are being reported at a rapid rate, the accountable thermokinetics of the entire process have rarely been studied. In order to exploit the versatility of this AM process for the desired properties of built mater...
Article
Currently, materials employed for use as consumable prosthetic devices possess uncontrolled degradation via corrosive action and inferior bio-integration characteristics. A material that is biocompatible and mechanically rigid is necessary for osseointegration. In an attempt to address these issues, a novel laser surface engineering approach was us...
Article
Magnesium and its alloys have been considered for consumable bio-implant applications due to their similar mechanical properties to the natural bone and biodegradability. Nevertheless, uncontrollable corrosion rate and limited bioactivity of Mg based materials in biological environment restrain their application. In light of this, objective of the...
Article
As a potential osteotomy tool, laser ablation is expected to provide rapid machining of bone while generating minimal thermal damage (carbonization) and physical attributes within the machined region conducive to healing. As these characteristics vary with laser parameters and mode of laser operation; the clinical trials and in-vivo studies render...
Article
High entropy alloys (HEA) offer the unique ability to tailor specific properties, such as wear resistance and corrosion resistance, for specific industrial applications. The purpose of this paper is to examine HEAs' ability to extend the life of forge punch die heads used in the forging industry. When a die head begins to crack or wear near the end...
Article
Here, we present a new combined freeze-casting and laser processing method for the design of yttria-stabilized zirconia (YSZ) based thermal-barrier coatings. YSZ ceramics with unidirectionally-aligned pore channels were created using the freeze-casting method. After sintering, top view and cross-sectional scanning electron microscopy (SEM) revealed...
Article
Full-text available
This work aims to understand the fundamental aspects of the laser-bone interaction in three-dimensional laser machining of the bone through an integrated experimental-computational approach. The study introduces 3-dimensional laser machining of bones through multi-laser passes and attempts to establish the dimensional control over the laser-machine...
Article
Biodegradable bone implants can remove the need for subsequent bone-implant surgeries by controlled biomineralization and degradation. Although Mg-alloys generally possess biocompatible properties, they corrode rapidly, thereby preventing sufficient hydroxyapatite formation and biomineral growth. In an attempt to address these limitations, laser su...
Article
Full-text available
The tools of the osteotomy have been advancing considering the challenges faced by their prior versions. The conventional mechanical tools pose various constraints in the development of osteotomy. This has brought many alternative non-conventional techniques with broad exploration space. Among these techniques, laser stands out as it offers several...
Article
Full-text available
Al–Co–Cr–Fe high-entropy alloy coatings were laser additively produced on aluminum substrate under diferent laser fuences (17.0–21.2 J/mm2 ). The resultant coatings consisted of a mixture of high-entropy and intermetallic phases, which resulted in marked improvement in hardness (~ 275–500 HV) as compared to the aluminum substrate (~ 30 HV). Coating...
Chapter
Volume 2A is a practical guide to aluminum and its engineering applications. It begins with a review of temper designations and product forms and the underlying physical metallurgy of aluminum alloys. It then examines manufacturing practices and techniques, focusing in critical areas such as casting, metalworking, heat treating, machining and finis...
Article
Laser‐assisted material processing is a promising field for new material synthesis. This study explores the feasibility of using laser as a tool to synthesize SiO2‐Na2O‐CaO‐P2O5 bioactive glass coatings on Ti‐6Al‐4V alloy for bio‐implant application. Various laser processing conditions were explored to investigate their effects on coating character...
Article
Full-text available
The corrosion is a major limiting factor for steel in the harsh environments and can be controlled by depositing protective passive coatings. Nickel-based alloy cladding of steel offers a solution by enabling better wear and corrosion resistance, and high bonding strength. The laser surface cladding of steel was conducted using a high-power direct...
Article
Grey cast iron, a widely used inexpensive alloy, typically exhibits inferior and spatially inconsistent hardness and wear behavior. Using laser glazing, the surface of grey cast iron has been uniformly hardened to 1000 HV0.2, an eight-fold increase from the base alloy. This paper clearly demonstrates that the exceptional increase in the surface har...
Article
Complex concentrated alloys (CCAs) represent a new class of alloy, which is typically multi-component with no base metal and exhibits a multi-phase microstructure. These alloys offer potentially improved properties over traditional alloys. In this study, after laser coating of a CrMoTaWZr CCA onto an H13 tool steel substrate was explored. H13 tool...
Article
Microstructural and corrosion characteristic of laser-alloyed TiB2/TiC/Al composite coatings on 6082-T651 aluminium substrate were investigated. Density functional theory was used to study the chemical bonding of TiC and TiB2. The results confirmed a compact TiB2/TiC/Al-coating with low porosity, without any cracks and with good long-term stability...
Chapter
Full-text available
This article focuses on a variety of laser beam machining (LBM) operations of aluminum and its alloys, namely, laser cutting, laser drilling, laser milling, laser turning, laser grooving, laser scribing, laser marking, and laser micromachining. It presents different approaches for carrying out machining operations, laser processing parameters, effi...
Chapter
Lasers evolved as a versatile materials processing tool due to their advantages such as rapid, reproducible processing, chemical cleanliness, ability to handle variety of materials, and suitability for automation. This article focuses on state-of-the-art laser applications to improve tribological performance of structural materials in lubricated an...
Article
This study describes the fundamentals of laser-bone interaction during bone machining through an integrated experimental-computational approach. Two groups of laser machining parameters identified the effects of process thermodynamics and kinetics on machining attributes at micro to macro. A continuous wave Yb-fiber Nd:YAG laser (wavelength 1070 nm...
Article
Full-text available
Although magnesium and magnesium alloys are considered biocompatible and biodegradable, they suffer from poor corrosion performance in the human body environment. In light of this, surface modification via rapid surface melting of AZ31B Mg alloy using a continuous-wave Nd:YAG laser was conducted. Laser processing was performed with laser energy ran...
Article
Effect of tensile loading on crystallisation behaviour of as-cast and laser thermal treated Fe–Si–B metallic glass foils was investigated. Tensile loading lacked any marked influence on the crystallisation behaviour of as-cast and structurally relaxed laser-treated metallic glass foils. Furthermore, the average crystallite/grain size in partially c...
Article
Abstract Fe–Si–B metallic glass foils were laser treated using a continuous wave Nd:YAG laser. Electrical resistivity and ultimate tensile strength of the laser treated foils were evaluated using four point probe method and Instron universal testing machine respectively in order to realize the structural changes during laser treatment. Electrical r...
Article
Laser joining with both longitudinal and transverse joining modes is reported for the plain carbon steel C1010 substrates using Fe48Cr15Mo14Y2C15B6 amorphous alloy filler. The high power (2000–3000 W) laser joining at the laser scanning speed of 6 mm/s resulted in complete fusion and full weld penetration of 3-mm thick steel substrates. Formation o...