Cohesive mechanism of the FeCr/Ni Interface: A first-principles study

Abstract

Based on previous experimental results, a series of FeCr/Ni interface models have been constructed and analyzed using a first-principles pseudopotential plane-wave method. Several parameters, such as the ideal work of separation (W), formation enthalpy (ΔH), cohesive energy (ΔE), and electronic structure were calculated in order to analyze the bonding performance and adhesion mechanisms of elements along an FeCr/Ni interface. The largest ideal work of separation was obtained for the Fe(100)/Ni(100) interface, which implies that this interface model presented the most stable structure among a series of crystal interface indices, e.g., (100), (110), and (111). With Cr doping, the W of the FeCr(100)/Ni(100) interface was increased by 101.571 mJ/m2. The corresponding ΔH and ΔE values also indicated that the FeCr(100)/Ni(100) interface model was strengthened by doping with chromium. Furthermore, the overlap population ratio, RLBOP (RLBOP= 1.04), of FeCr(100)/Ni(100) was smaller than that of Fe(100)/Ni(100) (RLBOP = 1.35), which implies that the toughness of the Fe(100)/Ni(100) interface can be improved by the presence of chromium impurities. Moreover, electronic structure analysis provided an understanding of the mechanical performance of the various Fe(Cr)/Ni interface models. Thus, our findings open a potential avenue for the comprehensive study of composite material designs.