Tensile Behavior of Cold Welded Metal-Metallic Glass: a Molecular Dynamics Simulation Study

Abstract

Work is done to study the joining mechanism and quality of cold welded joint of Al (metal) and Cu50 Zr50 (metallic glass), classical molecular dynamics (MD) simulation is carried out. Although many MD simulation has been carried out earlier for cold welding for materials like Au, Ag in the current study for the first time joint mechanism of Al (metal) and Cu50 Zr50(metallic glass) has been discussed. Embedded atom potential (EAM) has been used for simulation. During welding, an incomplete jointing area first forms through the interactions of the van der Waals attractive force, and the jointing area increases with increasing extent of contact between the two. A crystallization transition region forms in the jointing area for the welding of Al (metal) and Cu50 Zr50(metallic glass). Radial distribution function curve shows an atomic structure of welded area corresponding to different interference. As welding time increases more diffusion of metallic glass atom takes place in joint. Thus graph gets flat compare to starting period of welding. Strength of joint is checked by simulating sample for uniaxial tension test at the strain rate of 1.5 × 109/s corresponding to velocity of 30m/s. The stress-strain curves for the welded sample at the different extent of joints have plotted to show yielding, necking and rupture state each case. Maximum value for ultimate strength is attained for the interference at 1.3nm i.e. 626 MPa corresponding to strain value of 0.10. It can be seen that the amount of elongation follows sequence Al-Al>Al(metal)-Cu50 Zr50(metallic glass).