Azdiar A. Gazder

University of Wollongong | UOW · Electron Microscopy Centre

A Ti‐10V‐3Al‐3Fe metastable β Ti alloy is strained under three‐point bending conditions according to the ASTM E290‐14 standard. A combination of electron backscatter diffraction (EBSD) mapping and high‐resolution scanning transmission electron microscopy (STEM) is used to investigate the microstructural response to flexural stress. Results reveal a...

This study details the development and validation of a new algorithm that determines the dominant habit plane of a transformed child phase from orientation maps of a single planar cross-section. The method describes the habit plane in terms of its five-parameter grain boundary character and couples it to the specific orientation relationship of the...

Bismuth telluride-based alloys possess the highest efficiencies for the low-temperature-range (<500 K) applications among thermoelectric materials. Despite significant advances in the efficiency of p-type Bi2Te3-based materials through engineering the electronic band structure by convergence of multiple bands, the n-type pair still suffers from poo...

In this study, a Ni-based Hastelloy C276 alloy was prepared using cold metal transfer (CMT)-based directed energy deposition (DED) under different heat inputs with a zig-zag deposition path, integrated with active cooling and interlayer temperature control. Analogous mechanical properties were obtained for the fabricated alloys under different heat...

Microstructure evolution via deformation‐induced martensitic transformation, void formation, and crack propagation is investigated in a metastable austenitic Cr–Mn–N stainless steel for up to 90° bending using a combination of electron backscattering diffraction and parent grain reconstruction. Stress–strain heterogeneity and stress triaxiality stu...

The hybridization of additive manufacturing techniques with conventional forming processes offers significant reduction in production cost, time, and material wastage to produce near-net shaped components with refined microstructure and desired properties comparable to its wrought counterparts. In this work, the thermomechanical behavior and micros...

Stress-induced martensite formation is the predominant mechanism during the deformation of various functional and structural Ti- alloys. To predict the performance of these alloys, stress-induced martensite formation was modeled as a function of crystal orientation and stress state. We present an integrated micromechanical modeling approach using f...

The variant graph is a new, hybrid algorithm that combines the strengths of established global grain graph and local neighbor level voting approaches, while alleviating their shortcomings, to reconstruct parent grains from orientation maps of partially or fully phase-transformed microstructures. The variant graph algorithm is versatile and is capab...

A versatile generic framework for parent grain reconstruction from fully or partially transformed child microstructures has been integrated into the open-source crystallographic toolbox MTEX. The framework extends traditional parent grain reconstruction, phase transformation and variant analysis to all parent–child crystal symmetry combinations. Th...

The heterogeneous evolution of intragranular strain within polycrystalline copper grains is evaluated by in-situ electron back-scattering diffraction during uniaxial tension. Deformation heterogeneity between grains causes a proliferation of slip bands within grains and leads to lattice rotation within grains. The magnitude of intragranular orienta...

The variant graph is a new, hybrid algorithm that combines the strengths of established global grain graph and local neighbor level voting approaches, while alleviating their shortcomings, to reconstruct parent grains from orientation maps of partially or fully phase-transformed microstructures. The variant graph algorithm is versatile and is capab...

White etching layers (WELs) on rail surfaces play a crucial role in dictating rail life and guaranteeing safety during transport. It has been reported that the presences of WELs correlate with wheel-rail tribological properties and rail defects, including squats and studs. It is impossible to directly measure fracture mechanisms in WELs when rails...

Two transformation-induced plasticity steels, with and without Nb–Ti additions, were subjected to uniaxial tension after simulated thermo-mechanical processing. Electron back-scattering diffraction, with phase segmentation implemented during post-processing, was used to investigate the stability of retained austenite (RA) by analyzing its size, mor...

An extra low carbon martensitic stainless steel with 16% ultrafine grained metastable reverted austenite was subjected to uniaxial tensile testing and investigated with in-situ energy-dispersive synchrotron X-ray diffraction (XRD) and in-situ electron backscatter diffraction (EBSD) to reveal the complex interplay between stress, strain and martensi...

Current surface mechanical treatment techniques that produce gradient microstructures and return a combination of high strength and high uniform elongation are limited in terms of their industrial suitability. This study applies a modified surface rolling strategy, namely accumulative skin pass rolling (ASPR), to produce a gradient microstructure i...

Significant cost and time savings may be realised if multiple weld repairs are undertaken at the same location during the long-term maintenance of naval vessels. Consequently, this investigation simulates full-thickness hull welds, which are required to facilitate the removal and subsequent replacement of hull sections, by assessing the effects of...

A versatile generic framework for parent grain reconstruction from fully or partially transformed child microstructures was integrated into the open-source crystallographic toolbox MTEX. The framework extends traditional parent grain reconstruction, phase transformation and variant analysis to all parent-child crystal symmetry combinations. The inh...

Electron backscattering diffraction was used in-situ to track microstructure and texture development in polycrystalline copper during uniaxial tension. Characteristic of face-centred-cubic materials, copper develops a double fibre texture comprising a relatively strong 111 fibre and a weak 100 fibre parallel to the tensile axis. The observation of...

The deformation behaviour of a metastable β Ti–10V–2Fe–3Al (wt.%) alloy containing ~10 vol.% α phase was investigated via single-peak fitting and Rietveld refinement of in-situ neutron diffraction data collected during uniaxial tension. The formation of the 021α″ fibre is related to martensite variant selection during β → α″ transformation under ap...

Microstructure evolution, dominated by the formation of deformation-induced α″ martensite during the 3-point bending of a metastable β Ti–10V–2Fe–3Al alloy containing 5% α, was observed in-situ using forward-scatter electron imaging and electron backscattering diffraction. α″ plates nucleated heterogeneously from {580}α″ habit planes at α-β interfa...

In this study electron diffraction coupled with aberration-corrected STEM is used to unequivocally image, identify and confirm the structure producing the double diffracted spots seen in all electron diffraction patterns in twinned high carbon steels. The experimental and simulated data unequivocally show that regions comprising: (i) overlaps betwe...

A transformation-induced plasticity steel was thermomechanically processed and then transformed to bainite at an isothermal transformation temperature of 723 K for 1800 seconds, which exceeds the time required for completion of the bainite transformation. The formation of lenticular-shaped carbides with a triclinic lattice and internal substructure...

High-resolution in situ synchrotron X-ray diffraction was applied to study a cold-drawn and solution-treated 56Ni–44Ti wt% alloy subjected to uniaxial cyclic loading–unloading with incremental strains. The micro-mechanical behaviour associated with the partial and repeated B2↔B19′ phase transformation at the centre of the sample gauge length was st...

Annealed metastable β titanium (Ti) alloys comprise body-centred-cubic β and hexagonal-close-packed α phases and possibly, orthorhombic α'' martensite that forms on quenching or deformation. Electron backscattering diffraction is amongst the most popular methods for characterising such multi-phase microstructures. However, the crystallographic simi...

The ballistic performance of armour steel welds using austenitic filler materials is poor on account of the disparity in the mechanical properties of the weld and base metals. Consequently, a novel Keyhole Gas Tungsten Arc Welding process with a trapezoidal AISI309 austenitic stainless steel interlayer was developed to tailor chemical composition a...

EBSD in combination with aberration-corrected STEM is used to study the interfacial layer forming at Ni electrode - PbTe thermoelectric material interfaces. Contrary to previous studies, both orthorhombic and monoclinic phases are identified within the interfacial layer. EBSD and STEM data at interphase boundaries demonstrate an approximately smoot...

White etching layers (WELs) are one of the main causes of rail surface degradation, which play the important roles on the contact mechanism and tribology behaviours at wheel and rail interface. An electrical arcing due to current leakage was investigated as a new potential source of thermally induced WELs. Both electrical arcing induced WELs and ex...

The effect of compression–tension loading on the microstructure evolution in a fully annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning-induced plasticity steel has been investigated. Electron back-scattering diffraction was used to track a region of interest at true strains of 0 (initial), − 0.09 (after forward compression loading), and 0.04 (after rever...

In this study, a Ti-10V-3Fe-3Al alloy produced by the blended elemental powder metallurgy technique was subjected to two heat treatments at 675℃ and 625℃, resulting in lower β-phase stability and larger β-domain size in the sample heat treated at the higher temperature. The microstructural response to uniaxial tensile loading for the two conditions...

An Fe-17Mn-3Al-2Si-1Ni-0.06C wt pct high Mn steel was cold rolled to 42 pct thickness reduction, leading to a mixed microstructure of ε- and α′-martensite along with a trace amount of austenite (γ). The reverse transformation of ε- and α′-martensite to γ was tracked by in situ heating from room temperature up to 800 °C followed by 600 seconds holdi...

The present digital image correlation study characterised the local axial and shear strain fields of a 56Ni–44Ti wt.% shape memory alloy with an average grain size of 100 μm, under uniaxial monotonic and cyclic loading-unloading in tension. To elucidate the grain size effect, the results were compared with a previous investigation of the same alloy...

A cold-drawn and annealed 56Ni-44Ti wt% alloy was subjected to in-situ uniaxial monotonic tension in a synchrotron. Spatially resolved diffraction data was acquired along the gauge length by pausing the loading at five select macroscopic strains within the stress plateau region. This enables tracking localised transformation phenomena by sub-dividi...

Cold‐rolled to 42% thickness reduction and annealed at 500, 625, and 700 °C, an Fe–17Mn–3Al–2Si–1Ni–0.06C wt% steel is subjected to uniaxial tension and characterized via digital image correlation and electron back‐scattering diffraction. The cold‐rolled and 500 °C samples return similar microstructures comprising predominantly α′‐martensite and re...

The nucleation, coarsening and deformation accommodation mechanisms of ε-martensite in an Fe‐17Mn‐3Al‐2Si‐1Ni‐0.06C wt.% high manganese steel subjected to plane strain compression and cold-rolling up to 88% thickness reduction was studied using a combination of electron microscopy techniques. Intrinsic stacking faults in γ led to the nucleation of...

A Fe-17Mn-3Al-2Si-1Ni-0.06C wt.% steel was subjected to cold-rolling to 42% thickness reduction and isochronally annealed for 300 s between 500 and 850 °C. The high Mn steel was characterised via electron back-scattering diffraction, transmission electron microscopy and uniaxial tensile testing. The reversion of deformation-induced ε and α′-martens...

Electron back-scattering diffraction was used to track the microstructure evolution of a fully annealed Fe-24Mn-3Al-2Si-1Ni-0.06C TWinning Induced Plasticity (TWIP) steel during interrupted reverse (tension-compression) loading. Direct observation of the same selected area revealed that all deformation twins formed during forward tension loading (0...

Motivated by significant loss of mechanical properties during conventional fusion arc welding processes owing to under matching filler materials used and low efficiency associated with multipass welding, the viability of keyhole tungsten inert gas (K-TIG) welding for joining armour grade quenched and tempered (Q&T) steel was presented. Single pass...

This digital image correlation study details the mechanical behaviour and pattern evolution of the transformation band of a 56Ni-44Ti wt% shape memory alloy subjected to monotonic uniaxial and loading-unloading cycles in tension. The broadened single inclined band front and multiple criss-crossing patterns are found to relieve the in-plane moment c...

The present case study critically assesses the efficacy of a previously proposed segmentation methodology as a means to discriminate phases via post-processing the image of an elemental map. In the Bi2Te2.5S0.5 multiphase compound, the reference spectra of the Bi2Te3 and Bi2Te2S phases are distinct enough to effectively distinguish two phases durin...

The efficiency of thermoelectric generators is defined by the thermoelectric performance of materials, as expressed by the thermoelectric figure-of-merit, and their contacts with electrodes. Lead chalcogenide thermoelectric materials, and in particular PbTe, perform well in the 500 - 900 K temperature range. Here, we have successfully bonded bulk P...

The present case study compares transmission Kikuchi diffraction (TKD) with electron back-scattering diffraction (EBSD) on the same area of an electron transparent cross-section of a twinning induced plasticity steel. While TKD expectedly provides better clarity of internal defect substructures in the band contrast map, EBSD returns orientation dat...

A metastable β Ti-10V-3Al-3Fe (wt pct) alloy containing different α phase fractions after thermo-mechanical processing was compressed to 0.4 strain. Detailed microstructure evaluation was carried out using high-resolution scanning transmission electron microscopy and electron back-scattering diffraction. Stress-induced β → α′′ and β → ω transformat...

A recently modified Elasto-Plastic Self-Consistent (EPSC) model which empirically accounts for both intergranular and intragranular back stresses has been successfully used to simulate the cyclic (tension-compression) loading behaviour of an Fe-24Mn-3Al-2Si-1Ni-0.06 C TWinning Induced Plasticity (TWIP) steel between strain limits of ±1%. Lattice st...

The evolution of microstructure and micro-texture during discontinuous dynamic recrystallisation of an austenitic Ni-30Fe-Nb-C model alloy subjected to interrupted plane strain compression at strains (ε) of 0.23, 0.35, 0.68, 0.85 and 1.2 was investigated using electron backscattering diffraction and transmission electron microscopy. Throughout the...

Hydrogen-induced cold cracking and blistering in hydrogen-charged X70 steel was found to be highly dependent on microstructure, with the banded ferrite-pearlite microstructure of hot rolled strip showing a higher susceptibility than other microstructures produced by different thermal-mechanical routes. Although crack initiation was particularly sen...

The deformation-induced phase transformation of metastable austenite to martensite is accompanied by macroscopic plastic strain and results in significant work hardening and the delayed onset of necking. Steels that exhibit such transformation-induced plasticity (TRIP) effect possess high strength–ductility ratios and improved toughness. Since the...

A metastable β Ti-10V-3Al-3Fe (wt pct) alloy containing different α phase fractions after thermo-mechanical processing was compressed to 0.4 strain. Detailed microstructure evaluation was carried out using high-resolution scanning transmission electron microscopy and electron back-scattering diffraction. Stress-induced β → α′′ and β → ωtransformati...

Transmission Kikuchi Diffraction orientation mapping correlated with transmission microscopy observations was applied to a multi-phase TRIP-TWIP steel subjected to 66% cold-rolling and 625°C annealing. The cold-rolled microstructure and micro-texture suggests the possibility of variant selection in the ɛ and α′ phases at the local map scale. Upon a...

A high manganese TRIP-TWIP steel was cold rolled to 42% thickness reduction and isochronally annealed between 600 to 900 °C for 300 s. The microstructural evolution during annealing was studied by high resolution electron back-scattering diffraction. After cold rolling, the steel comprised predominant fraction of α'-martensite, a small fraction of...

This study applies the recently developed transmission Kikuchi diffraction technique to investigate the microstructures and micro-textures of a multi-phase Fe–17Mn–3Al–2Si–1Ni–0.08C wt% steel that concurrently exhibits twinning- and transformation-induced plasticity effects. The steel was cold rolled to 66% thickness reduction and subsequently anne...

In-situ neutron diffraction during cyclic tension-compression loading (∼+3.5% to −2.8%) of a 17Mn-3Al-2Si-1Ni-0.06C steel that exhibits concurrent transformation and twinning -induced plasticity effects indicated a significant contribution of intragranular back stresses to the observed Bauschinger effect. Rietveld analysis revealed a higher rate of...

Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced pl...

Undoped and carbon doped magnesium diboride $(hbox{MgB}_{2})$ cables have been assembled by braiding six Nb/Monel and Nb/Cu/stainless steel (SS) sheathed mono- and multifilament strands with a central copper stabilizer for improving the operational environment. This paper presents the fabrication and characterization of two types of in situ powder-...

X-ray diffraction was used to track the evolution of texture in a fully recrystallized Fe–24Mn–3Al–2Si–1Ni–0.06C TWinning Induced Plasticity steel subjected to uniaxial tensile testing. The bulk texture measurements returned the characteristic double fiber for fcc materials with a relatively stronger 〈111〉 fiber and a weaker 〈100〉 fiber parallel to...

A combination of X-ray diffraction and visco-plastic self-consistent (VPSC) modelling was used to track the texture evolution in an Fe–28Mn–0.28C twinning-induced plasticity steel subjected to cold-rolling between 12% and 80% thickness reduction. Texture measurements returned the characteristic α-fibre for low stacking fault energy face-centred-cub...

The through thickness texture gradient in accumulative roll bonding (ARB) processed materials is largely dependent on the friction between the rolls and the sheet during deformation. In this study, AA6061 aluminum alloy was pre-heated to 200 °C for 180 s and subjected to ARB deformation under dry conditions for up to 5 cycles using rolls with a hig...

A base low Si, high-Al transformation-induced plasticity (TRIP) steel and one with 0.03Nb and 0.02Ti (wt%) additions were subjected to thermo-mechanical processing (TMP) and galvanising simulations. The microstructure and mechanical properties were analysed using a combination of optical and electron microscopy, X-ray diffraction and tensile testin...

Abstract The microstructure and micro-texture evolution in an 80% and 90% cold drawn LCB-Ti alloy subjected to rapid annealing was analysed via electron back-scattering diffraction. The partially recrystallised microstructures were deconstructed into four fractions comprising deformed, recovered, newly nucleated and growing grains. The specific int...

The microstructure evolution of cold-rolled and isochronally annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning induced plasticity steel was investigated by electron back-scattering diffraction (EBSD). Deformation behaviour of a fully recrystallised sample was tracked in a selected area as a function of the true strain using a combination of interrupted t...

The effect of phases and steel processing on hydrogen uptake (diffusible and residual), surface and internal damage were evaluated using optical and scanning electron microscopy. The results have shown the fastest formation of blisters in ferrite-pearlite microstructure of strip, followed by equaixed ferrite-pearlite microstructure in normalised co...

The Visco-Plastic (VPSC) and Elasto-Plastic (EPSC) Self-Consistent models were applied to simulate the macroscopic stress-strain response and the evolution of crystallographic texture during the tensile loading of a fully annealed Fe-24Mn-3Al-2Si-1Ni-0.06C TWIP steel. Bulk texture measurements acquired by X-ray diffraction were used to validate the...

Abstract The evolution of lattice strains in fully annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning-induced plasticity (TWIP) steel is investigated via in situ neutron diffraction during cyclic (tension–compression) loading between strain limits of ±1%. The pronounced Bauschinger effect observed upon load reversal is accounted for by a combination of th...

Schmid’s law is used to predict the tendency of different grain orientations to deform via perfect slip, twinning, intrinsic and extrinsic faulting in a twinning-induced plasticity steel subjected to uniaxial tension. While the Schmid factors for twinning and intrinsic faulting are equivalent, the present analysis underscores the feasibility of twi...

A combination of electron back-scattering diffraction and X-ray diffraction was used to track the evolution of the microstructure and texture of a fully recrystallized Fe–24 Mn–3 Al–2 Si–1 Ni–0.06 C twinning-induced-plasticity steel during interrupted uniaxial tensile testing. Texture measurements returned the characteristic double fibre texture fo...

Advances in the development of new high strength steels have resulted in microstructures containing significant volume fractions of retained austenite. The transformation of retained austenite to martensite upon straining contributes towards improving the ductility. However, in order to gain from the above beneficial effect, the volume fraction, si...

In the present study, two powders near- β Ti alloys having a nominal composition of Ti-5Al-5Mo-5V-XCr-1Fe (X = 1 –2, wt%) were studied. The alloys were produced via the blended elemental powder metallurgy technique using hydrogenated Ti powder. Microstructure evolution and the distribution of the alloying elements between the phases were investigat...

Two near- β alloys, Ti-5Al-5Mo-5V-2Cr-1Fe and Ti-10V-3Fe-3Al, were produced by the blended element powder metallurgy technique. The use of (i) elemental powders with the Al-V master alloy in the case of Ti-5Al-5Mo-5V-2Cr-1Fe and, (ii) the complex Al-Fe-V master alloy in Ti-10V-3Fe-3Al has highlighted the influence of different alloying elements and...

The strain ageing and recrystallisation behaviour of conventional low carbon A06 steel was compared with those containing varying amounts of chromium (0.26, 0.52 and 0.74 wt.%). The results show that the A06 steel undergoes four stages of strain ageing: (i) the pinning by solute atoms of dislocations generated during pre-strain, (ii) the generation...

The effects of 0.74wt% Cr addition on the recrystallisation kinetics of low carbon (LC) steel was investigated using Vickers hardness testing, optical metallography and Electron Back-Scattering Diffraction (EBSD). Compared to the unalloyed steel, Cr addition significantly delays the time for recrystallisation and increases the JMAK pre-exponential...

A TWinning Induced Plasticity (TWIP) steel was cold rolled to 42% thickness reduction followed by isochronal annealing for 300 s between 600-850 °C. Bulk texture evolution during recrystallisation was investigated by X-Ray Diffraction. While the development of the α-fibre after cold rolling is typical of low stacking fault energy materials, anomalo...

TWinning Induced Plasticity (TWIP) steels have been recently developed as a promising material for automotive applications. In the present work the recrystallisation behaviour of 42% cold-rolled Fe-24Mn-3Al-2Si-1Ni-0.06C TWIP steel was investigated during isochronal annealing for 300s via microhardness testing, Electron Back-Scattering Diffraction...

Ti-stabilised interstitial free (IF) steel initially subjected to 8 passes, route BC equal channel angular pressing (ECAP) was further cold rolled (CR) at room temperature to 95% thickness reduction. Both samples were isothermally annealed at 710 °C following which their microstructures and micro-textures were compared via electron back-scattering...

The evolution of microstructure, micro-texture and mechanical properties during isothermal annealing of an ultrafine grained interstitial free (IF) steel processed by Equal Channel Angular Pressing (ECAP) followed by 95% cold rolling (CR) was studied. Microstructure and micro-texture changes were characterised by Electron Back-Scattering Diffractio...

The microtexture evolution of cold-rolled and isochronally annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning-induced plasticity steel is investigated by electron back-scattering diffraction. Novel deconstruction techniques are applied to cold-rolled and partially recrystallized maps. The formation of cold-rolling texture via composite slip/twin deformati...

The detailed evolution of microstructure and microtexture during the annealing of warm-rolled (WR) and cold-rolled (CR) 0.78 wt.% Cr extra-low-carbon steels was studied via electron back-scattering diffraction (EBSD). The partially recrystallized maps were deconstructed into deformed, recovered, newly nucleated and growing grain fractions using a n...

The evolution of microstructure, microtexture and mechanical properties during isothermal annealing of an ultrafine-grained interstitial-free steel after eight passes of route BC room temperature equal-channel angular pressing (ECAP) was studied. The microstructure and microtexture were characterized by electron back-scattering diffraction, and mec...

The microstructure and texture evolution of 42% cold-rolled Fe–24Mn–3Al–2Si–1Ni–0.06C TWinning Induced Plasticity (TWIP) steel is investigated during isochronal annealing at temperatures between 600 and 850 °C. In the cold rolled condition, bulk texture returned the distinctive α-fibre for low stacking fault energy materials, with higher intensitie...

Ti-stabilized interstitial free steel subjected to eight passes, route BC room temperature equal channel angular pressing (ECAP) additionally was cold rolled (CR) up to 95pct thickness reduction. Electron back-scattering diffraction and transmission electron microscopy characterized microstructural refinement and microtexture evolution, whereas the...

Fe–24Mn–3Al–2Si–1Ni–0.06C TWinning Induced Plasticity (TWIP) steel was 42% cold-rolled and isochronally annealed at temperatures between 600 and 850 °C. Optical, secondary and transmission electron microscopy found that a majority of as cold-rolled grains contain a large fraction of primary twin densities and a smaller fraction of secondary twins....

Atom probe tomography (APT) was used to study the evolution of clusters and fine precipitates during the annealing of severely deformed interstitial free steel. No dissolution of pre-existing Ti4C2S2 and FeTiP precipitates occurred during room temperature equal channel angular pressing (ECAP) and subsequent cold rolling. Ti rich clusters in the mat...

Two near-beta Ti-10V-3Fe-3Al and Ti-10V-2Fe-3Al alloys were produced by blended elemental powder metallurgy using hydrogenated titanium and V-Fe-Al master alloy powders. The distributions of the alloying elements were investigated at different stages of transformation of the heterogeneous powder compacts into the final homogeneous alloy product. Th...

A comparison between the microstructure, texture and mechanical properties of bcc interstitial-free (IF) steel and fcc copper (Cu) for up to N = 8 passes Equal Channel Angular Extrusion (ECAE) via route BC processing was undertaken. Transmission Electron Microscopy (TEM) and Electron Back-Scattering Diffraction (EBSD) studies revealed that the defo...

Interstitial-free steel and OFHC copper were subjected to 8 passes, route BC room temperature ECAE followed by cold-rolling up to 97.5% thickness reduction. Uniaxial tensile tests and Electron Back-Scattering Diffraction were used to characterise the evolution in mechanical properties, microstructure refinement and micro-texture. IF-steel showed co...

The evolution of stored energy and associated thermal behaviour was investigated for an ultrafine grained Ti-IF steel severely deformed by Equal Channel Angular Pressing (ECAP) followed by cold rolling at ambient and liquid nitrogen temperatures. Bulk stored energy measurements by Differential Scanning Calorimetry (DSC) returned 350-600 J/mol where...

A Ti-stabilised IF steel subjected to room temperature equal channel angular pressing (ECAP) for 8 passes, route BC was further cold rolled to 25, 50 and 95% thickness reductions. The evolution of bulk stored energy (350–600 J mol−1) and the associated thermal behaviour was investigated by differential scanning calorimetry (DSC). Local stored energ...

The Hall-Petch relationship was studied in interstitial-free steel subjected to Φ = 90° Equal Channel Angular Extrusion for up to N = 8 passes via route BC processing. The composite equation indicates that although low-angle grain boundaries provide the maximum strengthening up to N = 8 passes, the contribution from high-angle boundaries also incre...