Effect of Subgrain Boundary Distributions on Extra-Hardening of SPD-Processed Al-3%Mg Alloy

Taiki Morishige; Atsushi Kozaki; Tsutomu Tanaka

doi:10.4028/p-1OWAqU

Paper Titles

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Development of Non-Equimolar CoCrCuFeNi High Entropy Alloys for Aerospace Brazing
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Effect of Heat Treatment and Rolling Process on Microstructure and Deformation Behavior in Al-Si Alloy
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Effect of Subgrain Boundary Distributions on Extra-Hardening of SPD-Processed Al-3%Mg Alloy
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A Unique High-Temperature Deformation Mechanism in a CrMnFeCoNi Alloy
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Visualization of Dynamic Deformation Behavior of Al-Mg Alloys Using Electronic Speckle Pattern Interferometry
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HomeMaterials Science ForumMaterials Science Forum Vol. 1175Effect of Subgrain Boundary Distributions on...

Effect of Subgrain Boundary Distributions on Extra-Hardening of SPD-Processed Al-3%Mg Alloy

Abstract:

Ultra-fine-grained (UFG) Al alloys have excellent mechanical properties such as high tensile strength without remarkable loss of elongation. Severe plastic deformation (SPD) process is an effective method for obtaining UFG microstructure. SPD-processed Al alloys has extremely high strength than the extrapolated from Hall-Petch relationship due to their microstructure with residual excess strain after dynamic recrystallization. Especially, on account of Al alloys have high stacking fault energy, the dislocation rearrangement in the dynamically recrystallized grain is difficult to form high angle grain boundary. As a result, there are substantial dislocation wall and low-angle grain boundary after SPD processing. These dislocations remain in the grain after recrystallization and partially form low-angle grain boundaries and subgrain boundaries. Consequently, the strength increases from Hall-Petch relationship, which is the degree of extra-hardening, was measured up to 200 MPa in as-SPD processed Al-3%Mg alloy. The authors previously reported that the low-angle grain boundaries distributed in the microstructure after the repetitive equal-channel angular extrusion processing. The strength difference calculated by Bailey-Hirsch equations was not in accord with measured extra-hardened strength. In this study, the effect of grain boundary distributions on the extra-hardening was investigated by changing SPD-processing and subsequent annealing conditions.