Abstract

Background: Unlike the traditional crystalline metals, metallic glasses are lack of longrange order and have short-range order. Metallic glasses as amorphous alloys have excellent physical, chemical and mechanical properties, and have a broad application prospects in military, aerospace and sports equipment due to their unique microstructure. Currently, machining has been considered as a promising method to obtain MGs components with low surface roughness and high dimensional accuracy. In addition, it was found that the normal cutting force is substantially equal to the tangential forces in nanometric cutting of MGs by molecular dynamics simulation, which is different from that of crystal alloys. Therefore, the objectives of this paper are to investigate the effect of machining parameters on cutting forces in nanometric cutting process and analyze the microstructure evolution of the metallic glass workpiece.

Methods: The radial distribution functions were calculated to verify the amorphous state of workpiece. The microstructure of workpiece was used to analyze by the common neighbor analysis. In addition, the calculation of cutting forces was adapted to truncation radius method during all the simulations.

Results: There are no obvious changes of lattice structure in nanometric cutting of Cu₅₀Zr₅₀ MGs. The cutting force increases with the increase of cutting speed and depth and then keeps on a steady value in stable cutting process. Furthermore, the normal cutting force is substantially equal to the main cutting force during all nanometric cutting simulations of MGs and larger elastic recovery was founded on the machined surface.

Conclusion: Nanometric cutting at room temperature does not change the microstructures of Cu₅₀Zr₅₀MGs. There is no strain hardening in machining of MGs. Small elastic modulus will cause large elastic recovery on the machined surface. Therefore the normal cutting force is nearly equal to the main cutting force in nanometric cutting of MGs.

Keywords: Amorphous alloys, nanometric cutting, molecular dynamics simulation, radial distribution function.

Graphical Abstract