Molecular Dynamics Simulation of Deformation Mechanism of CuZr Metallic Glass under Nanoscratching with different Indenter Radius

Zhao Yue
Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
Li Qiyuan
Dongfang Electric Corporation Dongfang Turbine Co., Ltd, Deyang 618000, China
Zhao Fei
Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
Yu Jiaxin
Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
Lai Jianping
Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China

Abstract:

Molecular dynamics simulations were utilized to explore the deformation mechanism of CuZr metallic glass under nanoscratching with different indenter radius. When the scratches are performed using an indenter with a radius of 5 nm, with increasing the scratching cycle from one to five, the friction force decreases from 207.03 nN to 156.78 nN, which is attributed to the considerable surface hardening, manifested by the increase in scratch hardness from 29.48 GPa to 31.44 GPa. In contrast, in the case of the indenter with a 15 nm radius, the friction force exhibits a stabilized value of 150 nN with little fluctuations, which correlates well with the unchanged scratch hardness. Further analysis of the structure underneath the hardened surface reveals a densifying plastic flow during scratching, indicated by the smaller average atomic volume. By quantifying the amount of atomic clusters before and after scratching, it is found that the transformation of liquid-like clusters into solid-like clusters is responsible for the structural densification, which leads to surface hardening of metallic glasses subjected to scratching tests with an indenter of 5 nm radius.