Effect of Ag Content on Grain Growth during Reversion in Precipitation Hardened Cu-Cr-Zr-Ag Alloys

Effect of Ag content on grain growth during reversion in precipitation hardened Cu-Cr-Zr-Ag alloys has been studied. Changes in grain size and electrical conductivity during annealing at 900°C were investigated in the different Ag content alloys. Grain growth exponents n were derived from relation between annealing time and grain growth rate. For annealing time ranged from 500 s to 21.6 ks, the minimum grain growth exponent n of 0.09 was found in the alloy including Ag of 0.27 mass%. Effect of Ag addition on electrical conductivity for annealed alloys were analyzed according to the corrected Nordheim’s Rule, in which the calculated conductivity from binary phase diagrams Cu-Cr, Cu-Zr and Cu-Ag was higher than the practical value. These results suggested that Ag was effectively added to Cu-Cr-Zr ternary alloy to suppress grain growth of α phase in holding at elevated temperature and to increase solubility of Cr at 900°C in matrix.