A Review: Microstructural and Phase Evolution in Alloys during Extended Plastic Deformation

Bellon, Pascal; Averback, Robert S; Ren, Fuzeng; Pant, Nirab; Ashkenazy, Yinon

doi:10.1007/s11837-021-04709-8

Cited by 6 publications

(3 citation statements)

References 59 publications

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“…Detailed work by P. Bellon and group highlights the strain-dependent modes of microstructural evolution categorized by low strain (<100), where interfacial instabilities dominate, while at high strain (>100) where the atomic mixing can be seen. 6 , 7 Additionally, they propose the effective temperature model to explain the observation of high solute superstation tendencies under the high-strain regime. 7 , 8 However, another factor that can influence the experimental observations in these processes is the interaction of the deforming material with the ambient environment, which consists of reactive gases such as oxygen.…”

Section: Introductionmentioning

confidence: 99%

“… 6 , 7 Additionally, they propose the effective temperature model to explain the observation of high solute superstation tendencies under the high-strain regime. 7 , 8 However, another factor that can influence the experimental observations in these processes is the interaction of the deforming material with the ambient environment, which consists of reactive gases such as oxygen. In the past, metastable supersaturated phases and amorphous structures have been reported to form in several alloys (Nb–B, Cu–Ta, Cu–Nb, and Cu–Ag) on extended deformation by mechanical alloying.…”

Section: Introductionmentioning

confidence: 99%

“…These challenges limit the knowledge of the microstructural transformation pathways during such extended shear deformation processing. Detailed work by P. Bellon and group highlights the strain-dependent modes of microstructural evolution categorized by low strain (<100), where interfacial instabilities dominate, while at high strain (>100) where the atomic mixing can be seen. , Additionally, they propose the effective temperature model to explain the observation of high solute superstation tendencies under the high-strain regime. , However, another factor that can influence the experimental observations in these processes is the interaction of the deforming material with the ambient environment, which consists of reactive gases such as oxygen. In the past, metastable supersaturated phases and amorphous structures have been reported to form in several alloys (Nb–B, Cu–Ta, Cu–Nb, and Cu–Ag) on extended deformation by mechanical alloying. − In two examples, the grain boundary excess of oxygen in nanocrystalline (NC) Al was shown to inhibit the grain boundary migration, while the Zenner pinning effect of oxide nanoparticles was shown to stabilize the NC structure in the Fe–Mg ball-milled alloy .…”

Section: Introductionmentioning

confidence: 99%

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Extended Shear Deformation of the Immiscible Cu–Nb Alloy Resulting in Nanostructuring and Oxygen Ingress with Enhancement in Mechanical Properties

Gwalani

Pang

et al. 2022

ACS Omega

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Deformation processing of immiscible systems is observed to disrupt thermodynamic equilibrium, often resulting in nonequilibrium microstructures. The microstructural changes including nanostructuring, hierarchical distribution of phases, localized solute supersaturation, and oxygen ingress result from high-strain extended deformation, causing a significant change in mechanical properties. Because of the dynamic evolution of the material under large strain shear load, a detailed understanding of the transformation pathway has not been established. Additionally, the influence of these microstructural changes on mechanical properties is also not well characterized. Here, an immiscible Cu-4 at. % Nb alloy is subjected to a high-strain shear deformation (∼200); the deformation-induced changes in the morphology, crystal structure, and composition of Cu and Nb phases as a function of total strain are characterized using transmission electron microscopy and atom probe tomography. Furthermore, a multimodal experiment-guided computational approach is used to depict the initiation of deformation by an increase in misorientation boundaries by crystal plasticity-based grain misorientation modeling (strain ∼0.6). Then, co-deformation and nanolamination of Cu and Nb are envisaged by a finite element method-based computational fluid dynamic model with strain ranging from 10 to 200. Finally, the experimentally observed amorphization of the severely sheared supersaturated Cu–Nb–O phase was validated using the first principle-based simulation using density functional theory while highlighting the influence of oxygen ingress during deformation. Furthermore, the nanocrystalline microstructure shows a >2-fold increase in hardness and compressive yield strength of the alloy, elucidating the potential of deformation processing to obtain high-strength low-alloyed metals. Our approach presents a step-by-step evolution of a microstructure in an immiscible alloy undergoing severe shear deformation, which is broadly applicable to materials processing based on friction stir, extrusion, rolling, and surface shear deformation under wear and can be directly applied to understanding material behavior during these processes.

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