Skip over navigation

 

Molecular simulations of sputter deposition and mechanical properties of metallic glass thin films

Yunche Wang (National Cheng Kung University), Chunyi Wu (National Cheng Kung University)

From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A

Wed 3:10 - 4:30

CIT 227

Metallic-glass thin films exhibit unique mechanical properties due to its amorphous microstructures and deformation mechanisms. In this paper, the Cu-Zr-Al metallic-glass thin films on the titanium crystalline substrate were obtained by using molecular dynamics (MD) for sputter deposition simulation. The simulated deposition allows natural construction of the interface between the film and substrate. The deposition simulations adopted a tight-binding potential with consideration of argon working gas from with the pair-wise Moliere potential. The as-deposited films were amorphous and used as initial structures for mechanical properties simulations, including indentation, tension/compression, as well as shear loading. All simulations were carried out at elevated temperatures to compare with experimental data. The radial distribution function of the film is calculated and compared with synchrotron experimental data. From the mechanical property simulations, the hardness and elastic modulus of the films were calculated, as well as the pileup index under different depth-to-thickness ratios. Our MD simulation results are consistent with experimental data. Furthermore, atomic stress and strain were calculated to reveal deformation localization. In addition, elastic constants of the film and associated degrees of elastic anisotropy are studied to correlate structural anisotropy and to reveal structural relaxation. It is found that the deposited and MD-equilibrated films have notable anisotropic elastic constants, and their relaxation can be observed at the MD time scales.