Density functional theory investigation on the stability, adhesion strength, tensile properties and fracture behavior of γ-Fe/Cu heterogeneous nucleation interface

Abstract To theoretically study the stability and the heterogeneous nucleation characteristics of γ-Fe/Cu interface in steel/copper bimetallic, the six surface models and seven interface models were investigated through density functional theory. Besides, the interface stability, adhesion energy, electronic properties, tensile process and fracture behavior of three kinds typical Fe/Cu interface model were calculated by first-principles calculations. Simultaneously, the mechanism on heterogeneous nucleation of pure Fe on Cu-based alloy was revealed. The results indicate that the bramfitt’s lattice mismatches of all the three Fe/Cu interfaces were both 4.11%, and all the Cu surfaces and the Fe surfaces were trends to converge, when the number of layers were 9 and 7, respectively. Among three kinds Fe/Cu interfaces with HCP structure, the Fe (1 1 0)/Cu (1 1 0) interface shown higher strength of metallic bonds and stable ionic properties. When the strain is 37%, the maximum value of the tensile stress is about 20.3GPa and the electron density between Fe and Cu atoms drop to disappear. The calculated adhesion work of Fe (1 1 0)/Cu (1 1 0) interface with HCP structure is 1.88 J/m2, is higher than that between Cu/Cu melt (1.78 J/m2), which proved that the Fe particles can promote heterogeneous nucleation of Cu atoms and then account for the grain refinement of Cu-based alloy.