块状金属玻璃Zr55Cu30Al10Ni5的微压痕尺寸效应

基于Drucker-Prager屈服准则,建立了适用于描述压敏材料的低阶应变梯度塑性(CMSG)理论. 通过ABAQUS自定义材料子程序(UMAT),构造了CMSG理论本构计算的有限元格式,并对块状金属玻璃Zr₅₅Cu₃₀Al₁₀Ni₅的圆锥压痕实验响应进行了数值模拟分析. 计算结果与实验数据相吻合,表明该理论可以很好地描述金属玻璃的弹塑性行为. 在此基础上,研究了不同压深下的载荷位移曲线和硬度,计算结果显示该材料的硬度随着压痕深度的增大而减小,表明基于Drucker-Prager屈服准则的CMSG理论可以预测金属玻璃Zr₅₅Cu₃₀Al₁₀Ni₅在微米尺度下表现出来的尺寸效应现象. 此外,通过分析不同摩擦因数下材料的载荷位移曲线,表明摩擦力对该材料微压痕响应的影响可以忽略不计.

Micro Indentation Size Effect of a Zr55Cu30Al10Ni5 Bulk Metallic Glass

The study evaluated the micro indentation size effect of a Zr55Cu30Al10Ni5 bulk metallic glass. Firstly, a conventional theory of mechanism-based strain gradient plasticity (CMSG) for pressure-sensitive materials was built based on the Drucker-Prager yield criteria. Secondly, the finite element format of the constitutive relation of the CMSG theory was set up using the user-defined material subroutine (UMAT) interface of the commercial software ABAQUS. Thirdly, the conical indentation test response was simulated and analyzed via the subroutine UMAT and verified by experiments. The results show that CMSG theory can accurately describe the elastic-plastic behavior of the materials. Finally, the load-displacement curve and hardness of the material under different indentation depths were studied on the basis of the previous results. It is clear that the hardness of metallic glass increases with indentation depth decreasing, indicating that the CMSG theory can predict the size effect of the metallic glass Zr₅₅Cu₃₀Al₁₀Ni₅ in micro scales. Furthermore, analysis of load-displacement curves under different friction coefficient demonstrates that the micro indentation response of the material is hardly affected by friction.