1993 Volume 34 Issue 5 Pages 438-442
The grain boundary reactions in Ag–Cu alloys with or without 1.5 mass%Sn were investigated by optical microscope, electric resistivity, SEM, and hardness tests. The results are summarized as follows.
Electric resistivity, hardness, and nodule formation were investigated as a function of aging time for 93Ag–7Cu and 91.6Ag–6.9Cu–1.5Sn alloys at temperatures between 250 and 350°C.
With aging time, the electric resistivity of Sn-added alloy decreased rapidly and reached a constant value after passing a minimum.
In the 91.6Ag–6.9Cu–1.5Sn alloy, very fine particles of β-Cu were precipitated in the α′-Ag phase with Cu supersaturation at the initial stage of the aging treatment at each temperature, while nodule formation was significantly retarded. The reverse was observed for the 93Ag–7Cu alloy.
