The Critical Cooling Rates Determined by the Jominy Tests in the Age-Hardening Cu–Cr, Cu–Be and Cu–Co₂Si Alloys

抄録

The Cu-0.7% Cr alloy, the Cu-2.5% Be-0.3% Co alloy, and the Cu-4% Co₂Si alloy were used with the object of studying the critical cooling rate (CCR) for the solution treatment of an age hardening copper base alloy. The author introduced an idea of the critical cooling rate, defining it as the cooling rate necessary to obtain a supersaturated solid solution at room temperature. In this paper the critical cooling rate of each alloy was determined by Jominy end quenching methods using a specimen of 25 mm diameter and 100 mm length. The CCR obtained was 17°C/sec at 925°C for the Cu–Cr alloy, 60°C/sec at 500°C for the Cu–Be alloy, and 20°C/sec at 940°C for the Cu–Co₂Si alloy.