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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Quasi-in-situ EBSD study of the thermal stability of gradient twinning microstructure of an AZ31B magnesium alloy processed by laser shock peening
AU - Liu, Q.
AU - Sun, W.
AU - Chu, S.
AU - Wang, Y.
AU - Zhou, B.
AU - Wang, H.
AU - Mao, B.
PY - 2025/3/31
Y1 - 2025/3/31
N2 - In this study, the thermal stability of gradient microstructure in the commercial AZ31B magnesium (Mg) alloy processed by laser shock peening (LSP) is systematically explored using quasi-in-situ electron backscatter diffraction (EBSD) measurement. The mechanisms of grain growth and twinning evolution of LSP-processed AZ31B Mg alloy during the annealing treatment at 300 °C are revealed. The experimental results demonstrate that there is a significant transformation of a gradient twinning microstructure into an almost twin-free microstructure, and the trend of grain growth is associated with LSP-induced strain energy storage. From the topmost surface to the sublayer of LSP-processed sample, the grain growth is mainly driven by the migrations of twin boundaries (TBs) and high-angle grain boundaries (HAGBs), respectively, which is attributed to the reduced accumulated strain energy along the LSP direction. It was demonstrated that the {101¯2} tension twins possess the capability to engulf non-corresponding parent phases, which transcends the conventional understanding that twins interact solely with their corresponding parent grains. The twins not only interact with the parent grain but also have the capacity to engulf twins of adjacent parent grains. In contrast, the isolated twins within the parent grains struggle to grow during annealing, indicating that {101¯2} tension twins have excellent thermal stability. The findings of this work can contribute to an in-depth understanding of the thermal stability and the grain growth mechanisms of LSP-induced gradient twinning microstructure in Mg alloys and provide the potential for the microstructure optimization to improve the comprehensive mechanical properties.
AB - In this study, the thermal stability of gradient microstructure in the commercial AZ31B magnesium (Mg) alloy processed by laser shock peening (LSP) is systematically explored using quasi-in-situ electron backscatter diffraction (EBSD) measurement. The mechanisms of grain growth and twinning evolution of LSP-processed AZ31B Mg alloy during the annealing treatment at 300 °C are revealed. The experimental results demonstrate that there is a significant transformation of a gradient twinning microstructure into an almost twin-free microstructure, and the trend of grain growth is associated with LSP-induced strain energy storage. From the topmost surface to the sublayer of LSP-processed sample, the grain growth is mainly driven by the migrations of twin boundaries (TBs) and high-angle grain boundaries (HAGBs), respectively, which is attributed to the reduced accumulated strain energy along the LSP direction. It was demonstrated that the {101¯2} tension twins possess the capability to engulf non-corresponding parent phases, which transcends the conventional understanding that twins interact solely with their corresponding parent grains. The twins not only interact with the parent grain but also have the capacity to engulf twins of adjacent parent grains. In contrast, the isolated twins within the parent grains struggle to grow during annealing, indicating that {101¯2} tension twins have excellent thermal stability. The findings of this work can contribute to an in-depth understanding of the thermal stability and the grain growth mechanisms of LSP-induced gradient twinning microstructure in Mg alloys and provide the potential for the microstructure optimization to improve the comprehensive mechanical properties.
KW - Deformation twinning
KW - Gradient microstructure
KW - Laser shock peening
KW - Magnesium alloy
KW - Thermal stability
KW - Grain boundaries
KW - Grain growth
KW - Twinning
KW - AZ31B magnesium alloys
KW - Diffraction measurements
KW - Diffraction studies
KW - Electron back scatter diffraction
KW - Electron backscatter diffraction
KW - Energy
KW - Thermal
KW - Magnesium alloys
U2 - 10.1016/j.matchar.2025.114769
DO - 10.1016/j.matchar.2025.114769
M3 - Journal article
VL - 221
JO - Materials Characterization
JF - Materials Characterization
SN - 1044-5803
M1 - 114769
ER -