Effect of pre-existing shear bands on mechanical properties and serration behaviors in bulk metallic glasses |
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Authors: | Xu-dong Yuan Sheng-hai Wang Kai-kai Song Xiao-liang Han Yu-sheng Qin Dong-fang Li Xue-lian Li Bo Song Hui Xing Li Wang |
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Affiliation: | 1. School of Mechanical, Electrical & Information Engineering, Shandong University (Weihai), Weihai 264209, Shandong, China;2. School of Science, Northwestern Polytechnical University, Xi′an 710072, Shaanxi, China |
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Abstract: | Pre-existing (multiple) shear bands were introduced into the ductile Zr56 Co28 Al16 and Zr65 Ni10 Cu15 Al10 bulk metallic glasses (BMGs) through the lateral-deformation, respectively.It was found that the pre-exi-ting shear bands can further enhance the compressive plasticity of ductile BMGs.According to the serra-tion analysis on the plastic deformation of the as-cast and the pre-deformed samples, the serration events in the stress-strain curves during deformation display a self-organized critical (SOC) behavior.Compared with the as-cast BMGs, a larger power-law scaling exponent calculated based on serrated flow behaviors becomes larger for the pre-deformed BMGs, implying that the shear banding stability of BMGs is effec-tively enhanced.This should be caused by the pronounced interactions of shear bands during plastic de-formation for the pre-deformed BMGs.However, by introducing a large amount of multiple shear bands into the glassy matrix, it also becomes easier for shear bands to propagate along the pre-existing shear bands, leading to a lower cut-off elastic energy density for the pre-deformed BMGs.More multiple shear bands with stronger interactions for the pre-deformed BMGs could provide a larger chance to activate the shear-band cracking but less local elastic energies are remained for the subsequent crack-linking. |
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Keywords: | Bulk metallic glass Shear band Serration Ductility Pre-deformation |
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