MD-based study on the deformation process of engineered Ni–Al core–shell nanowires: Toward an understanding underlying deformation mechanisms

Abstract

Abstract Nowadays, core/shell structures due to very high thermal and electrical conductivity are taken into account in the manufacture of many industrial sensors and catalysis. Ni–Al core/shell structures are known as one of the most practical materials due to their high chemical stabilities at elevated temperatures. Since the evaluation of the mechanical properties of the industrial core/shell catalysts is crucial, identification of the mechanism responsible for their plastic deformation has been a challenging issue. Accordingly, in this study, the mechanical properties and plastic deformation process of Ni–Al core/shell structures were investigated using the molecular dynamics method. The results showed that due to the high-stress concentration in the Ni/Al interface, the crystalline defects including dislocations and stacking faults nucleate from this region. It was also observed that with increasing temperature, yield strength and elastic modulus of the samples decrease. On the other hand, increasing the temperature promotes the heat-activated mechanisms, which reduces the density of dislocations and stacking faults in the material. Consequently, the obstacles in the slip path of the dislocations as well as dislocation locks are reduced, weakening the mechanical properties of the samples.