Numerical Analysis of Effects of Compressive Strain on the Evolution of Interfacial Strength of Steel/Nickel Solid-State Bonding

Abstract

A molecular dynamics (MD) simulation of the solid-state bonding between single crystals of bcc iron and fcc nickel, i.e., dissimilar components, was conducted by hot-pressing with various initial compressive strains ranging from 14 to 20% and subsequent uncompressed isothermal holding at 873 K. Then, the intrinsic strength of the interfaces with various isothermal holding times was evaluated by uniaxial tensile technique. It was found that the interface separation follows the traction-separation law and that always take place either at the interface or close to the interface. The intrinsic strength of the interface is very low under an as-compressed condition and tends to rapidly increase in the early stage of isothermal holding. In addition, lower intrinsic strength was observed in a specimen with higher initial compressive strain. The significant increase in the intrinsic strength is attributed to the short-range atomic rearrangement of a layer of disordered atoms at the interface, driven by energy stored from the compressive deformation.