Temperature and loading rate effect on the load-displacement response of metalmetallic glass (Al-Cu50Zr50) layered structure during nano-indentation

Abstract

Molecular dynamics (MD) simulations of nano-indentation on metal-metallic glass (Al-Cu50Zr50) multilayer is carried out to investigate the load-displacement response, mechanical properties and deformation mechanisms. The indentation study is carried out at temperatures in the range of cryogenic to room temperature (10 K-300 K). The indenter speeds are varied between 0.5-5 Å/ps to study the effect of loading rate. The interaction between atoms Al, Cu, and Zr are defined by EAM (Embedded Atom Method) potential. A sample size of 200 Å (x) × 200 Å (y) × 200 Å (z) comprising of 538538 atoms is used for nano-indentation. NVT ensemble and P P S boundary conditions are used along x, y and z directions. We observed a peak load of 117 nN, at a temperature of 10 K with a loading rate of 5 Å/ps. We found that with an increase in loading rate, the peak load increases. As anticipated, the increase in temperature decreases the strength of the multilayer. The atomic displacement vector plots reveal that MG act as obstacles to the movement of dislocations nucleated at the interface.