Revealing microstructure evolution and strengthening behavior of high- temperature laser shock peened copper

J Liu and YL He and XH Zhang and YW Hu, MATERIALS CHARACTERIZATION, 209, 113706 (2024).

DOI: 10.1016/j.matchar.2024.113706

Laser shock, an advanced technology for material processing at ultrahigh strain rates, has demonstrated significant potential in the field of metal strengthening. The mechanical properties of the metals obtained are typically associated with the resultant microstructure following severe plastic deformation. Given the significant impact of processing temperature on microstructure evolution during mechanical deformation, this study explored the microstructure evolution and corresponding strengthening behavior of pure copper after hightemperature laser shock peening processes. The results demonstrated that, in comparison to room temperature laser shock peening, the ultrahigh strain rate thermomechanical deformation occurring in the high -temperature laser shock peening facilitated the continuous dynamic recrystallization process of copper, thus promoting the high quality generation of gradient nanograin structures. Further investigations indicated that following hightemperature laser shock peening treatment, the copper sheet exhibited synchronous enhancements in both strength and ductility. The deformation mechanisms of the gradient nanograins obtained were further revealed, encompassing plasticity induced by nanotwins, mechanically driven migration of grain boundaries, and concurrent grain growth. The synergy of the cross -scale gradient grains induced by the high temperature laser shock peening process was revealed to be the concealed mechanism behind the enhanced mechanical properties of the copper.

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