The Cu–Mg–P system: precipitation phenomena and physical properties

Abstract

The Cu–Mg–P system has interesting properties. A detailed study of the precipitation process and its effect on the physical properties has been made. The solubilities of magnesium and phosphorus in copper are rather high. Solubility is reduced drastically in the ternary system through the formation of Mg₃P₂. The shape of a quasi-binary section Cu–Mg₃P₂ is proposed. Segregation during solidification is pronounced and results in a complex mixture of non-equilibrium phases. The kinetics of the precipitation process have been studied. The rate of precipitation is slow in a recrystallized structure but faster after cold working. The precipitates dissolve rapidly when the alloy is heat treated to temperatures above 600°C. Finely dispersed precipitates give a hardening effect and restrain recrystallization. It is possible to obtain very high tensile strength and a conductivity of 70%10 IACS by a combination of precipitation and cold deformation.