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Main Authors: Birch, Jonathan, Jenkins, Emily, Vrettou, Anastasia, Said, Mohammed, Vashishtha, Himanshu, Connolley, Thomas, Brooks, Jeff, Collins, David M.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2406.10140
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author Birch, Jonathan
Jenkins, Emily
Vrettou, Anastasia
Said, Mohammed
Vashishtha, Himanshu
Connolley, Thomas
Brooks, Jeff
Collins, David M.
author_facet Birch, Jonathan
Jenkins, Emily
Vrettou, Anastasia
Said, Mohammed
Vashishtha, Himanshu
Connolley, Thomas
Brooks, Jeff
Collins, David M.
contents The mechanisms that govern a previously unexplained hardening effect of a single phase Cu-30wt%Zn α-brass after heating have been investigated. After cold-work, the alloy possesses an increased yield strength and hardening rate only when heat treated to temperatures close to 220{^\circ}C, and is otherwise softer. Crystallographic texture and microstructure, explored using electron backscatter diffraction (EBSD), describe the deformation heterogeneity including twin development, as a function of heat treatment. When heated, an increased area fraction of deformation twins is observed, with dimensions reaching a critical size that maximises the resistance to dislocation slip in the parent grains. The effect is shown to dominate over other alloy characteristics including short range order, giving serrated yielding during tensile testing which is mostly eliminated after heating. In-situ X-ray diffraction during tensile testing corroborates these findings; dislocation-related line broadening and lattice strain development between as worked and heated α-brass is directly related to the interaction between the dislocations and the population of deformation twins. The experiments unambiguously disprove that other thermally-induced microstructure features contribute to thermal hardening. Specifically, the presence of recrystallised grains or second phases do not play a role. As these heat treatments match annealing conditions subjected to α-brass during deformation-related manufacturing processes, the results here are considered critical to understand, predict and exploit, where appropriate, any beneficial process-induced structural behaviour.
format Preprint
id arxiv_https___arxiv_org_abs_2406_10140
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A micromechanical study of heat treatment induced hardening in α-brass
Birch, Jonathan
Jenkins, Emily
Vrettou, Anastasia
Said, Mohammed
Vashishtha, Himanshu
Connolley, Thomas
Brooks, Jeff
Collins, David M.
Materials Science
The mechanisms that govern a previously unexplained hardening effect of a single phase Cu-30wt%Zn α-brass after heating have been investigated. After cold-work, the alloy possesses an increased yield strength and hardening rate only when heat treated to temperatures close to 220{^\circ}C, and is otherwise softer. Crystallographic texture and microstructure, explored using electron backscatter diffraction (EBSD), describe the deformation heterogeneity including twin development, as a function of heat treatment. When heated, an increased area fraction of deformation twins is observed, with dimensions reaching a critical size that maximises the resistance to dislocation slip in the parent grains. The effect is shown to dominate over other alloy characteristics including short range order, giving serrated yielding during tensile testing which is mostly eliminated after heating. In-situ X-ray diffraction during tensile testing corroborates these findings; dislocation-related line broadening and lattice strain development between as worked and heated α-brass is directly related to the interaction between the dislocations and the population of deformation twins. The experiments unambiguously disprove that other thermally-induced microstructure features contribute to thermal hardening. Specifically, the presence of recrystallised grains or second phases do not play a role. As these heat treatments match annealing conditions subjected to α-brass during deformation-related manufacturing processes, the results here are considered critical to understand, predict and exploit, where appropriate, any beneficial process-induced structural behaviour.
title A micromechanical study of heat treatment induced hardening in α-brass
topic Materials Science
url https://arxiv.org/abs/2406.10140