A molecular dynamics study on the mechanical properties of Fe-Ni alloy nanowires and their temperature dependence

Fe-Ni alloy nanowires are widely used in high-density magnetic memories and catalysts due to their unique magnetic and electrochemical properties. Understanding the deformation mechanism and mechanical property of Fe-Ni alloy nanowires is of great importance for the development of devices. However, the detailed deformation mechanism of the alloy nanowires at different temperatures is unclear. Herein, the deformation mechanism of Fe-Ni alloy nanowires and their mechanical properties were investigated via the molecular dynamics simulation method. It was found that the local atomic pressure fluctuation of the Fe-Ni alloy nanowire surface became more prominent with an increase in the Ni content. At low temperature conditions (<50 K), the plastic deformation mechanism of the Fe-Ni alloy nanowires switched from the twinning mechanism to the dislocation slip mechanism with the increase in the Ni content from 0.5 at% to 8.0 at%. In the temperature range of 50-800 K, the dislocation slip mechanism dominated the deformation. Simulation results indicated that there was a significant linear relationship between the Ni content, temperature, and ultimate stress in the temperature range of 50-800 K. Our research revealed the association between the deformation mechanism and temperature in Fe-Ni alloy nanowires, which may facilitate new alloy nanowire designs.