Atomistic simulations of improved thermal stability and strength of nanocrystalline copper films by alloying with Zr

The effects of Zr solute content and temperature on the thermal stability and thermal mechanical properties of nanocrystalline (NC)-Cu alloyed with Zr at grain boundaries (GBs) are studied using molecular dynamics simulations. The simulation results show that doping 1% Zr into NC-Cu significantly increases structural stability and prevents grain growth at a high temperature of 1000 K via the effect of GB pinning. The number of dislocations that nucleate and propagate significantly decreases with increasing Zr content. Zr doping elongates the elastic deformation phase. Young's modulus decreases with increasing Zr content (in the range of 2%-6%) and temperature. Doping Zr into NC-Cu enhances mechanical strength and ductility at temperatures of 300-800 K.