Effects of testing conditions on the deformation behaviour of a Ti-based bulk metallic glass

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:766

Article

Chu, Qiaoling^1,5  Xu, Shuai¹  Zhu, Xiaofei²  Zhu, Zhengwang³  Zhang, Haifeng³  Bai, Ruixiang⁴  Lei, Zhenkun⁴  Yan, Cheng⁵ 

[1] Xian Univ Technol, Sch Mat & Engn, Xian 710048, Shaanxi, Peoples R China

[2] Shenyang Univ Technol, Sch Mat & Engn, Shenyang 110870, Liaoning, Peoples R China

[3] Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Shenyang 110014, Liaoning, Peoples R China

[4] Dalian Univ Technol, State Key Lab Struct Anal Ind Equipment, Dalian 116024, Peoples R China

[5] Queensland Univ Technol, Fac Sci & Engn, Sch Chem Phys & Mech Engn, Brisbane, Qld 4001, Australia

关键词: Bulk metallic glass;    Shear band;    Loading rate;    Nanoindentation;   

DOI  :  10.1016/j.msea.2019.138404

来源: Elsevier

【 摘 要 】

This study investigated the deformation behaviour of a Ti32.8Zr30.2Ni5.3Cu9Be22.7 bulk metallic glass via indentation and compression tests with loading rate ranging from 30 mu N/s to 30000 mu N/s. The load-displacement (P-h) curves show evident displacement bursts (pop-in events). The statistic analysis reveals that the pop-in events are correlated to the loading rate, i.e., the pop-in size increasing linearly with the indentation depth and decreasing exponentially with the loading rate. Cube corner indenter with much sharper geometry favours the promoting of pronounced pop-in events, compared to Berkovich indenter. Similar loading rate effect can be observed in the micro-pillar compression tests. SEM observation of the deformed pillars reveals that the shear bands (along a similar to 50.7 degrees plane with respect to the loading axis) initiate from the side wall and run across the entire pillars. The free-volume theory and shear transformation zone (STZ) are used to explain these observations quantitatively. The serration to smooth shape of P-h curves is most likely due to the simultaneous operation of multiple shear bands at high loading rate while the single shear band contribution could not be resolved.

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