Satyam Suwas

• Ph.D.
• Professor at Indian Institute of Science Bangalore

The present investigation aims to explore the response of stress relieving and solution annealing heat treatment on fracture toughness and tensile properties in two distinct routes of AM, namely selectively laser melted (SLM) and wire arc additively manufactured (WAAM) stainless steel 316L. The stress relieving treatment was done at 600 °C and solu...

This study investigates the microstructural, mechanical, corrosion, and biological behaviors of spark plasma sintered (SPS) zinc (Zn) samples for biomedical applications. The findings reveal that SPS significantly refines the grain structure of pure Zn compared to the conventional casting method. The SPS process, conducted at a lower sintering temp...

This study investigates the shock response of forged and annealed commercially pure magnesium (Cp–Mg) and its cerium (Ce)‐alloyed variants (Mg–0.5Ce and Mg–3Al–0.5Ce). Shock loading is performed using a conventional shock tube setup at two pressure levels along the forging direction (FD). Under low‐pressure conditions, all materials deform without...

In this current study, polycrystal modelling has been utilized to understand the anisotropic dwell fatigue behavior of Cp titanium along rolling and transverse directions. A 2D microstructure of polycrystalline Cp titanium obtained through Electron Back Scattered Diffraction (EBSD) microstructure which is used to study the heterogeneous stress dist...

In the present work, the microstructure and texture evolution in commercially pure titanium subjected to blast assisted deformation has been investigated by means of electron backscattered diffraction and transmission electron microscopy. The evolved texture in the deformed material is primarily attributed to the dominant ⟨1010⟩ 64.4° contraction t...

The present work compares the microstructure–mechanical property correlation in stainless steel 316L manufactured through three important and distinct additive manufacturing routes, namely, laser powder bed fusion (LPBF), electron beam powder bed fusion (EBPBF), and wire arc additive manufacturing (WAAM). The choice of opting these routes comes as...

The present investigation addresses the evolution of microstructure and texture due to site-specific solidification conditions in additively manufactured stainless steel 316L by Laser Powder Bed Fusion (LPBF) technique. Experiments were designed with increasing dimensionality from 1D to 3D that simulates and deconvolutes the different factors influ...

The yield strength (σy.s.) of directed energy deposited near-α Ti-6Al-2Sn-4Zr-2Mo alloy exceeds 1000 MPa while possessing very low ductility of less than 10%. The possibility of enhancing the ductility without a significant decrease in the σy.s. is via judicious heat treatment which transforms the as-built martensitic α′ into an α/β phase mixture,...

This study investigates the microstructure and mechanical properties of Inconel 718 (IN718) manufactured via electron beam melting (EBM). The EBM‐processed IN718 exhibits a unique grain structure with columnar grains along the build direction (BD) and equiaxed grains perpendicular to it. Contrary to typical solidification textures, the strongest te...

In this work, the effect of high-pressure torsion (HPT) deformation has been investigated for solution-treated (ST) AA2099 aluminium alloy. The strength of the alloy has been found to increase with deformation to an equivalent strain (εeq) ~ 27, beyond which it saturates. X-ray line profile analysis and transmission electron microscopy (TEM) reveal...

Cold dwell fatigue is a well-known phenomenon in titanium alloys where stress holds at ambient temperatures, reducing fatigue life. This study investigates the anisotropy of dwell fatigue behaviour of the IMI834 in a forged billet along axial and transverse directions experimentally and correlates it with 2D microstructure using crystal plasticity...

Additive manufacturing (AM) is a layer-by-layer manufacturing process which can build complicated parts in near net shape. We have utilized selective laser melted implants to treat deformities in upper limb. For this purpose, a workflow was established. Bone models were generated from X-ray computed tomography (CT-scan) data. Bone models were desig...

This study examines cyclic and dwell fatigue crack initiation and growth in well forged, low microtexture intensity Ti 6242 alloy. The statistics of crack occurrence have been explored in cross-sections of samples that failed in cyclic and dwell fatigue. Cracks are observed dominantly on the basal planes of the primary α grains with a high Schmid f...

Laser shock peening without coating (LSPwC), a prospective surface modification technique for improving the mechanical aspects of Ti-6Al-4V alloy for automotive/aerospace sector, is also expected to dictate the efficiency of this material class for implant application. Here we unravel the impact of LSPwC on Ti-6Al-4V material surface characteristic...

In this study, a TiNbCrTa refractory complex concentrated alloy (RCCA) was prepared using vacuum arc remelting. The microstructural evolution and mechanical properties of both as-cast and heat-treated RCCA samples were analyzed. Heat treatment (HT) was performed at 800–1200 °C for 1 h in a vacuum-sealed environment. These samples exhibited a format...

Strength and ductility vary inversely due to a rapid decrease in dislocation storage capacity with the pronounced increase in work hardening rate at the expense of ductility in most conventional and recently designed advanced ductile materials. This limitation can be overcome by creating heterogenous or hierarchical microstructures containing not o...

Strengthening during low‐temperature annealing is a common observation in several nanocrystalline and ultrafine‐grained materials. The origin of such strengthening is generally attributed to various recovery processes leading to restricted dislocation motion. Herein, the observations on recovery‐induced strengthening in cold‐rolled (CR) equiatomic...

This work aimed to manufacture Ti–28.5Nb and Ti–40.0Nb (wt%) alloys in situ via selective laser melting (SLM) from Ti and Nb elemental powders.

The effect of Sc addition to AA2195 (NoSc) alloy by 0.025 wt% (LoSc) and 0.25 wt% (HiSc) on the evolution of microstructure, texture and mechanical property in AA2195 alloy during room temperature HPT processing was studied by electron microscopy, X-ray diffraction and Vicker’s microhardness test, respectively. Higher amount of Sc addition increase...

Herein, the development of directional solidification for a novel high‐temperature Mo–20Si–52.8Ti (at%) ternary alloy using a modified Bridgeman type apparatus is presented. The resulting alloy exhibits a microstructure consisting of a body‐centered cubic solid solution (BCC ss ) and a hexagonal silicide (Ti,Mo) 5 Si 3 with approximate volume fract...

In industrial applications, welding of dissimilar metals such as aluminum (Al) and titanium (Ti) is a prerequisite for the development of hybrid components with improved mechanical and corrosion properties. However, dissimilar welding of the Al/Ti system is highly challenging due to differences in the physical and thermal properties of the two mate...

The effect of niobium (Nb) content in titanium aluminide (TiAl) with the composition Ti–45Al–(5, 10)Nb–0.2B–0.2C manifests in terms of change in the sequence of phase evolution during solidification. In the present investigation, the consequent evolution of microstructure, phases, and crystallographic texture has been examined for the survived soli...

A multi-scale investigation was carried out on pure silver subjected to equal channel angular pressing up to 3 passes. Microstructure and texture were examined using scanning and transmission electron microscopy as well as diffraction of neutron and high-energy synchrotron radiation. The evolution of the deformation substructure in the material is...

The influence of texture on strength was investigated by altering the amount of cobalt in Ni-Co alloys. The purpose of incorporating Co was to reduce the stacking fault energy (SFE) of the alloy. A decrease in the SFE reduces the ease of cross-slip and enhances planar slip, leading to changes in texture during cold working. Three Ni-Co alloys (33,...

Mg-Li-based alloys, being the lightest alloys, are attractive for aerospace applications. We have optimized Li content as 8 wt% and Zn content as 2 wt% in Mg to obtain tensile properties better than the existing commercial and experimental wrought Mg-Li-based alloys, which has been discussed in another paper. In this manuscript, we present the elec...

Additive manufacturing (AM) enables the fabrication of patient-specific implants of complex geometries. Although selective laser melting (SLM) of 316L stainless steel (SS) is well established, post-processing is essential to preparing high-performance biomedical implants. The goal of this study was to investigate surface mechanical attrition treatm...

The fatigue life of additively manufactured 316L stainless steel (SS) in an aqueous corrosive medium is shown to improve markedly when the surfaces were processed by surface mechanical attrition treatment (SMAT). SMAT induced surface nano-crystallization owing to severe plastic deformation and yielded a gradient microstructure beneath the surface o...

In dissimilar friction stir welding (FSW), the influence of tool position with respect to the weld interface (tool-offset) on the microstructural evolution and its effect on joint formation, particularly considering the difference in deformation behavior of the two joining materials, has not been fully explored. This investigation highlights the in...

The present work is aimed at examining the effect of solid solution on the development of recrystallization microstructure and texture in FCC materials where SFE remains unchanged on alloying addition. To elucidate the mechanisms of texture formation during recrystallization, pure Ni and Ni-Fe (20 and 40 wt.% Fe) alloys were investigated. After rec...

The evolution of the microstructure and texture of a newly developed Mg alloy Mg-6.9Sn-2.6Zn (TZ73) and its effect on tensile behaviour has been studied as a function of strain path change during hot rolling. The two strain paths employed are cross-rolling plus unidirectional rolling (CR-UDR) and reverse rolling (RR). The RR process led to a slight...

The present study describes the hot deformation behaviour of a novel Ti–6Al–4Mo–1V–0.1Si alloy. The flow characteristics of the alloy were investigated in the strain rate range of 0.01 s−1 to 10 s−1 and at temperatures ranging from 800 to 1050 °C. The increase in deformation temperature and decrease in strain rate results in gradual decrease of flo...

Fatigue pre-cracked four-point bend specimens of a rolled AZ31 Mg alloy are loaded asymmetrically and their mixed-mode (I and II) fracture behaviour is contrasted with pre-notched samples. In-situ mapping of displacement and strain fields is performed through optical imaging coupled with digital image correlation analysis. The fracture surface morp...

Wire arc additive manufacturing (WAAM) offers a high rate of material deposition among various additive manufacturing techniques with wire as feedstock material but has not been established for zinc alloys. Zn alloys can be used as degradable biomaterials, in contrast to conventional permanent metallic biomaterials. In this work, commercially pure...

In this work, the dwell fatigue sensitivity of the alloy IMI 834 has been investigated as a function of microstructures obtained through three different thermomechanical processing routes. The different thermomechanical process routes led to three different product forms of IMI 834, namely, forged billet, hot rolled bar and forged cylinder. All the...

Laser-based powder-bed fusion (LPBF) / Selective laser melting (SLM) was used to fabricate a eutectic composition of Al-33Cu alloys in-situ. Different scan strategies (1×1, 2×2, 3×3, 4×4, and 60°) were adopted to understand its effect on porosity, phase formation, microstructural and texture evolution, and mechanical properties. The 1×1 specimen sh...

Multiphase ferrite-bainite-martensite (F-B-M) microstructure processed through rolling and two-step cooling in a V-microalloyed steel exhibited excellent stability under strain-controlled fatigue. The steel exhibited a steady state response and even cyclic hardening up to a total strain amplitude of 0.6% and displayed a cyclic softening response at...

This study examines the deformation behaviour of Ni-Co microwires exhibiting high strengths and ductility, where the addition of Co is intended to decrease the stacking fault energy. A reduction in stacking fault energy is likely to retard the recovery processes, refine grain size and enhance strain hardening by dislocation interactions at twin bou...

This study deals with the microstructure and texture effects on strength in tension and torsion testing of nickel microwires. Wire drawing was used to produce four different batches of microwires with a diameter of 100 μm with different mechanical treatments. Tension tests showed strain hardening with increasing yield strength upon an increase in d...

This investigation proposes a pathway for generating optimum microstructure for a medium Mn containing twinning-induced plasticity/transformation-induced plasticity (TWIP/TRIP) steels. The steel contains a two-phase microstructure consisting of austenite and ferrite phase arranged in a lamellar fashion. The microstructure was developed following a...

In the present study, high-temperature deformation behavior and creep response have been investigated for an additively manufactured eutectic high-entropy alloy (AM EHEA) with the composition AlCoCrFeNi2.1. The microstructure revealed L12 and bcc phases. High-temperature compression studies show that the yield strength tends to increase with the in...

The effect of different solutionizing temperature and cooling rate on the extent of recovery, recrystallization and texture evolution in the alloy Ti-6Al-4V (Ti-64) has been investigated in different microstructural conditions. The hot rolled Ti-64 alloy was subjected to three different heat treatments in order to obtain three different microstruct...

Mode I, static fracture experiments and uniaxial tension/compression tests are conducted at three temperatures in the range from 25 to 100∘C using fatigue pre-cracked four-point bend and micro-tensile/compression specimens machined from a rolled AZ31 Mg alloy plate. Digital image correlation technique along with in-situ optical imaging is employed...

Titanium is the prevalent material of choice for metallic implantable devices. However, post-operative bacterial infections remain a major cause of implant failure. Mechanobactericidal surfaces have garnered much attention due to their ability to neutralize bacteria, via physical forces and interactions instead of traditional chemical routes. In th...

AM30 magnesium alloy was subjected to annealing at temperatures ranging from 200 to 450°C for 1–1440 min to evaluate the microstructure and texture evolution during grain growth. The grain growth exponent of n = 9 and activation energy of Q = 105.6 KJ/mol were observed. Precipitates, such as Mg17Al12, Al8Mn5 and Al11Mn4 were observed in the alloy,...

Additive manufacturing (AM) of biomedical alloys such as Co-Cr-Mo alloys holds immense potential for fabricating implants with complex geometry and tailored to meet patient-specific needs. However, layer-by-layer fabrication in AM processes results in undesired anisotropy due to the solidification texture and grain morphology. The present study aim...

WE43 magnesium alloy was modified using surface mechanical attrition treatment (SMAT) and characterized to evaluate the influence of sub-micron surface modification on degradation rate and in vitro behavior. Modified surface was characterized for wettability, hardness, roughness, degradation rate, in vitro biocompatibility, and antibacterial activi...

The effects of microstructure and texture on the mechanical properties of Mg and its alloys have been investigated in the present study. Samples, such as pure Mg, AM30 (Mg–3 wt.% Al−0.3 wt.% Mn), and AME300 (Mg–3 wt.% Al–0.3 wt.% Mn–0.2 wt.% Ce) alloys, were used for the investigation. The samples in the form of hot-rolled plates were subjected to...

The dynamic transformation of austenite to ferrite occurs in various steels and has technological implications for grain refinement. Despite significant research, ambiguities persist about the nature of this transformation, its driving force, and the influencing parameters. In the current work, these outstanding issues are addressed through a study...

In the present work, the microstructural evolution in heavily cold-rolled and annealed Fe-6.8Al low-density steel has been studied. The evolution of texture with a strong component 001⟨110⟩ has been observed upon cold rolling. After recrystallisation, the formation of texture with 111110 component and other γ fiber orientations with weak intensitie...

Spheroidization is a common technique to improve the formability and machinability of material. Multiple combinations of deformation level and annealing time were employed to optimize the microstructure in 22MnB5 steel, aiming to achieve maximum spheroidization and keeping the process most economical. The critical annealing temperature for spheroid...

Laser powder bed fusion (L-PBF) was attempted here to additively manufacture a new generation orthopedic β titanium alloy Ti-35Nb-7Zr-5Ta toward engineering patient-specific implants. Parts were fabricated using four different values of energy density (ED) input ranging from 46.6 to 54.8 J/mm3 through predefined laser beam parameters from prealloye...

In the present study, the microstructure and texture evolution during cold drawing of commercially pure (CP) titanium wires have been investigated. The roles of initial grain sizes, reduction percentages and strain-rates of deformation were also examined. Both tensile and compressive twins were observed in the samples after cold drawing, and the tw...

The strength–ductility trade-off is an eminent factor in deciding the mechanical performance of a material with regard to specific applications. The strength–ductility synergy is generally inadequate in as-synthesized high entropy alloys (HEAs); however, it can be tailored owing to its tunable microstructure and phase stability. Thermo-mechanical p...

Severe plastic deformation (SPD) is effective in producing bulk ultrafine-grained and nanostructured materials with large densities of lattice defects. This field, also known as NanoSPD, experienced a significant progress within the past two decades. Beside classic SPD methods such as high-pressure torsion, equal-channel angular pressing, accumulat...

Mg–3Al–0.2Ce alloys were subjected to annealing at temperatures ranging from 200 to 450°C for different periods to evaluate the microstructure and texture developments in the alloy. The grain growth exponent of n = 13 and the activation energy for grain growth, Q = 75 kJmol⁻¹ were observed. A large number of precipitates were observed in the sample...

An as-cast AM30 Mg alloy was homogenized at 400 °C for 24 h and rolled at 350 °C by symmetric rolling (SR), asymmetric rolling (ASR), and asymmetric rolling combined with reverse rolling (ASR + RR). The grain size marginally decreased from SR to ASR to ASR+RR processes. The low-angle grain boundaries (LAGBs) percentage was in the order ASR+RR > ASR...

The mechanical behavior of a cast CuMnNiFeCo high entropy alloy, with larger grains and 0.5% (by volume) of micro-porosities, was investigated at room temperature under a unidirectional tensile load. The initial microstructural features show two types of the Face Centered Cubic (FCC) structure (FCC-1 and FCC-2), corresponding to the dendritic arms,...

Additive manufacturing (AM) is being widely explored for engineering biomedical implants. The microstructure and surface finish of additively manufactured parts are typically different from wrought parts and exhibit limited bioactivity despite the other advantages of using AM for fabrication. The aim of this study was to enhance the bioactivity of...

AM technologies allow for the fabrication of complicated geometric components at reduced costs and with better functionality. Aside from design complexity, regulating desired textures during AM processes can provide a substantial advantage. Microstructures are typically columnar along the build direction and equiaxed across the build plane. Columna...

Third generation γ-titanium aluminides with nominal compositions Ti–45Al–5Nb–0.2B–0.2C and Ti–45Al–10Nb–0.2B–0.2C were investigated to identify the phase transformation and their morphological stability with temperature. Electron microscopy and differential scanning calorimetry were employed for the characterization of phases and for recording the...

This study deals with the evolution of strength and microstructure in pure nickel during wire drawing from an initial diameter of 1.74 mm to 30 μm, corresponding to a total true strain of 8.1. Electron backscattering diffraction (EBSD) and X-ray diffraction (XRD) have been used for microstructural characterization. In the later stages of deformatio...

This study elucidates the mechanism of texture induced planar anisotropy in ambient temperature (∼25°C) dwell fatigue response of an annealed sheet of commercially pure titanium (cp-Ti). Dwell fatigue resistance on loading along rolling direction (RD) was observed to be markedly superior when compared to the loading along transverse direction (TD)....

The evolution of microstructure and texture during selective laser melting (SLM) of silver alloy - sterling silver 925 (AM Ag925) has been investigated and analyzed vis-à-vis cast sterling silver (AC Ag925). The microstructure of AM Ag925 was characterized by a single-phase silver-rich face-centered cubic solid solution with dendritic morphology, a...

An anomalous deformation texture evolution has been observed in high-stacking-fault-energy pure platinum during cold rolling. A maximum of 98% thickness reduction, equivalent to a true strain of 3.9, was imposed. The evolution of texture observed during rolling is characterised as sluggish and the starting texture was retained up to very large roll...

Inspired by the outstanding properties of cobalt-base superalloys, an effort has been made to develop cobalt-base high entropy alloy for high temperature applications based on valance electron concentration (VEC). The newly developed cobalt-base high entropy alloy exhibited a two-phase microstructure with nano lamellar eutectic morphology. The cons...

Additive manufacturing (AM) has emerged as an alternative tool to overcome the challenges in conventionally processed metallic components. It is gaining wide acceptability because of the superior properties of the manufactured components compared to their wrought processed counterparts. Among the available AM processed materials, austenitic stainle...

As the global trauma fixation devices market expands rapidly, it is imperative to improve the production of fixation devices through enhanced design accuracy and fit for best performance and maximum patient comfort. Selective laser melting (SLM) is one of the mature additive manufacturing methods, which provides a viable route for the rapid product...

Magnesium and its alloys have the potential to serve as a revolutionary class of biodegradable materials, specifically in the field of degradable implants for orthopedics. However, the corrosion rate of commercially pure magnesium is high and does not match the rate of regeneration of bone tissues. In this work, magnesium alloys containing zinc and...

In the present investigation, hot deformation behaviour of Fe–21Cr-1.5Ni–5Mn alloy was studied by performing isothermal unidirectional hot compression tests. The tests were carried out at strain rates of 0.01, 0.1, 1, 5 and 10 s⁻¹ and at temperatures of 675, 750, 825, 900, 975 and 1050 °C. The samples were deformed up to 50% height reduction (ε = 0...

Surface severe plastic deformation (S2PD) of additively manufactured/three-dimensional (3D) printed metallic parts is gaining increased attention as a post-manufacturing operation to enhance the material performance in a wide variety of applications. Surface mechanical attrition treatment (SMAT) is an S2PD technique that can yield a nanostructured...

Equiatomic CrMnFeCoNi high-entropy alloy was cold- and hot-rolled (room temperature and 700 °C) to a thickness reduction of 90%. Subsequently, the rolled samples were annealed for 1 h at temperatures between 450 °C and 800 °C. The microstructure and texture of as-rolled and annealed samples were studied by scanning electron microscopy coupled with...

Among the additive manufacturing processes, selective laser melting has gained wide popularity for manufacturing austenitic stainless steel (316L) due to the inherent advantages offered. The synergetic effect of non-equilibrium microstructure and crystallographic texture on mechanical properties has shown that its properties can be tuned by control...

Metal additive manufacturing processes offer unique opportunities for the biomedical industry owing to their ability to produce custom-designed implants with near-net shape and intricate geometry. Co–Cr alloys are among the most popular metallic biomaterials due to their excellent resistance to both corrosion and wear. Several studies have been rep...

The role of shear strain and deformation temperature on the microstructure and texture evolution in commercially pure (CP) titanium was investigated in the present study. CP titanium samples were subjected to free-end torsion at elevated temperatures, starting from room temperature (298 K) to 873 K, for different shear strains of 0.5–2.5. Deformati...

Out of several methods, one of the most explored strategies to decrease the lattice thermal conductivity of Co4Sb12-based materials are either filling suitable electropositive elements into the voids or the formation of nanocomposites. These two approaches were combined in this work by filling Yb into the void of Co4Sb12 and preparing nanocomposite...

The current focus of research in Mg alloys is to develop wrought Mg‒based alloys suitable for automotive applications. The challenges to be overcome are low strength, poor ductility, and high cost associated with Mg‒based alloys. With this objective, wrought Mg–7Sn–3Zn (TZ73) alloy has been developed in the present work, which does not contain expe...

This study investigates heterogeneity in the deformation of an annealed sheet of commercially pure titanium (cp-Ti), its variation with loading direction and its influence on dwell fatigue response. Cp-Ti sheet with a typical cold rolling texture was deformed, along its rolling direction (RD) and transverse direction (TD), to the same strain level...