Grain boundary heredity from Cu/Al solid-liquid interface via diffusion during the solidification processes

Using molecular dynamics (MD) simulations with the embedded atomic method (EAM), we explored the solidification process of Cu/Al solid-liquid interface where Cu has complex grain boundary structures. The simulation results show that if there is a vertical grain boundary in solid Cu, the Cu atoms near the grain boundary diffuse into the liquid Al region and form a horizontal grain boundary of CuAl after cooling, that is grain boundary heredity. The underlying physics of such grain boundary heredity is attributed to different diffusion rate of Cu atoms close to the grain boundary, and the geometric structure information of Cu grain boundary can be reflected in CuAl regions. The position of horizontal grain boundary can be dramatically influenced by the cooling rate. Our work offers insight into the defect and structural evolution during alloy solidification process, which can provide new approach to designing desirable alloy compounds.