No abstract

No abstract

DIGM phenomenon is very similar to the diffusion process and the coupled migration of the reaction front occured in discontinuous precipitation. It is likely to postulate that DIGM may occur in the system where discontinuous precipitation appears. W. Kim and co-author have Investigated DIGM In six copper alloy systems (Ag/Cu, Mg/Cu, Sb/Cu, In/Cu, Cd/Cu and Sn/Cu) in which discontinuous precipitation has been found. In Kim s experiment, the diffusion treatments were conducted at 400 °C and 450 °C for 4 days, Kim found DIGM occurred in 4 systems, i. e. Sb/Cu, In/Cu, Cd/Cu and Sn/Cu, but in Ag/Cu and Mg/Cu systems no DIGM was found.In order to test whether there is DIGM or not in Ag/Cu system, we reexamlned the DIGM phenomenon in Ag/Cu under 400 °C and 480 °C for 5 days diffusion, finally DIGM was found in this system. In different segments of a same boundary the bulging directions and the migration distances may be different as indicated in Fig. 1.

No abstract

The characteristics of thickening kinetics of the intermetallic compounds (IMC) (Cu 6 Sn 5 + Cu 3 Sn) during aging at 120 C and 90 C in solid state were studied by quantitative metallographic analysis for three solder alloy systems: 40Sn-Bi/Cu, 40Sn-Bi-2Ag/Cu and Sn-37Pb/Cu. The diffusion couple were prepared by hot immersion in the molten solder bath. The results showed that the rate of the IMC thickening increases in the order Sn-37Pb/Cu 40Sn-Bi/2Ag/Cu 40Sn-Bi/Cu. The IMC thickening rate in the Sn-Bi eutectic system is one order of magnitude faster than that in Sn-Pb eutectic system. The time exponents are different from each other. The relationship between the increase of IMC and aging time follows a parabolic function in Sn-Pb system, and a linear relation in Sn-Bi system. Addition of Ag in Sn-Bi inhibits the IMC thickening process.