Diffusion-Induced Grain Boundary Migration (DIGM) in Cu-In Alloy

Diffusion-induced grain boundary migration (DIGM) has been studied in pure Cu and a Cu-l0at%In alloy during alloying between 693 and 773 K (420 and 500 C) and during de-alloying between 783 and 823 K (510 and 550 C), respectively. Although the partial pressures of In above Cu-In alloys at the annealing temperatures are relatively low, it is demonstrated that the vapor transport of In is sufficient to cause DIGM. The morphology of DIGM for the case of alloying was similar to that described for alloying in Cu-Zn and Fe-Zn alloys. Also the temperature dependence of the DIGM boundary migration rate has been measured and gives an activation energy of Q - 179 kJ/mol. Microhardness tests confirmed that alloyed zones have a higher hardness than pure Cu. For the case of de-alloying, new fine grains were observed to form near the grain boundaries on the surface of specimens by diffusion induced recrystallization