Diffusion mechanism and kinetics of diffusion bonded Mg/Ni/Al joint

Mg and Al were bonded successfully by means of diffusion bonding using Ni interlayer. The microstructure, diffusion mechanism and regulation of atom diffusion were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis analysis (EPMA). The results showed that the joints consisted of Mg-Ni interface and Al-Ni interface, and there were Mg2Ni formed in the Mg-Ni interface and Al3Ni formed in the Al-Ni interface, respectively. Diffusion activation energy of Mg and Al were lower than that of Ni in the Mg-Ni and Al-Ni interface. The thickness (x) of Mg2Ni and Al3Ni can be expressed as x(2) = 3.97x10(-4) exp (-139600/RT) (t-t(0)) and x(2) = 8.62x10(-3) exp (-174200/RT) (t-t(0)) with heating temperature (T) and holding time (t).