Discussion of Microstructure and phase constituents in the interface zone of Mg/Al diffusion bonding

In a recent article, Liu et al. described the formation of phases during the diffusion bonding of A1 to Mg at temperatures in the range 450 degrees C to 490 degrees C and pressures in the range 0.08 to 0.10 MPa. They present micrographs of the phases in the weld zone resulting from welding at 480 degrees C and 0.08 MPa for 60 minutes and a concentration-distance plot resulting from welding at 470 degrees C and 0.08 MPa for 60 minutes. However, the mechanism they propose for the formation of the phases in the weld zone is incorrect. It is the purpose of the present discussion to provide a correct analysis of the formation of the phases in the weld zone.