ORCID Profile
0000-0002-6075-2525
Current Organisation
Oregon State University
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Publisher: MDPI AG
Date: 02-01-2020
DOI: 10.3390/MET10010077
Abstract: Aluminum alloys can be used in the fabrication of intricate geometry and curved parts for a wide range of uses in aerospace and automotive sectors, where high stiffness and low weight are necessitated. This paper outlines a review of various research investigations on the superplastic behavior of aluminum alloys that have taken place mainly over the past two decades. The influencing factors on aluminum alloys superplasticity, such as initial grain size, deformation temperature, strain rate, microstructure refinement techniques, and addition of trace elements in aluminum alloys, are analyzed here. Since grain boundary sliding is one of the dominant features of aluminum alloys superplasticity, its deformation mechanism and the corresponding value of activation energy are included as a part of discussion. Dislocation motion, diffusion in grains, and near-grain boundary regions being major features of superplasticity, are discussed as important issues. Moreover, the paper also discusses the corresponding values of grain size exponent, stress exponent, solute drag creep and power law creep. Constitutive equations, which are essential for commercial applications and play a vital role in predicting and analyzing the superplastic behavior, are also reviewed here.
Publisher: Elsevier BV
Date: 05-2022
Publisher: MDPI AG
Date: 18-12-2020
Abstract: CoCrNi equiatomic medium entropy alloy sheets were prepared by asymmetric rolling, cryorolling, and asymmetric cryorolling. The asymmetric cryorolled s les exhibited a noteworthy ultra-fine-grain heterogeneous lamella structure. The microstructure and corresponding hardness obtained by different rolling processes and subsequent annealing are compared. It can be seen from the results that the cryogenic deformation temperature had a stronger effect on the mechanical properties of the medium entropy alloys (MEA), compared with the shear strain caused by the asymmetric cryorolling. The effect of annealing temperature on texture components and volume fractions of the specially rolled s les was also analyzed. The result revealed that the recrystallized MEA exhibited similar texture components and the corresponding volume fraction, which indicated that the rolling process had limited influence on the formation of annealing texture. The recrystallized texture after annealing retained the deformation texture and twin related orientations appeared. Asymmetric rolled MEA showed strong random composition than symmetric rolled MEA regardless of rolling temperature. The recrystallized textures of the species obtained by the three rolling processes did not exhibit a significant dependence on the annealing temperature.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Wiley
Date: 06-09-2023
Abstract: The cold angular rolling process (CARP) is being developed as a continuous severe plastic deformation (SPD) technique, which can process metal sheets without any length limitations at room temperature. CARP contains cold rolling and equal‐channel angular process components. The sheet thickness is kept consistent before and after CARP, allowing multiple passes of the sheet. The desired microstructure and mechanical properties can be achieved in the processed metallic sheets. The current study is aimed to evaluate the capability of CARP by processing copper sheets with different sheet widths for repetitive passes. The CARP‐treated sheets are examined by lab‐scale X‐ray and high‐energy synchrotron X‐ray diffraction to investigate the evolution in dislocation density, texture, and strain anisotropy, and by tensile testing to identify the bulk mechanical properties. The digital image correlation (DIC) method is applied to tensile testing so that strain localization within the s le gauge was visualized and deformation behavior was evaluated after yielding till post‐necking by estimating the hardening exponent and strain hardening rate of the CARP‐treated sheet. Comparing the reported continuous and multiple‐step processes on Cu and its alloys, the present study confirms CARP is potentially a useful sheet process for strengthening ductile metals. This article is protected by copyright. All rights reserved.
No related grants have been discovered for Laxman Bhatta.