Preparation of Cu/Invar composites by powder metallurgy

Abstract

An orthogonal experiment scheme was employed to study the influences of forming pressure, sintering temperature and holding time and Cu content on microstructure, hardness and electrical resistivity of the Cu/Invar composites prepared by the powder metallurgy (PM) technique. The interdiffusion of the Fe, Ni and Cu atoms of the composites during sintering was also investigated. The results show that the Invar alloy is distributed continuously in the composites, when the Cu content is 30 wt-% and below; when the Cu content is 40 wt-% and above, a continuous net structure of Cu forms. Properties, especially the electrical and thermal conductivities, depend on the relative density and atom interdiffusion of the Cu/Invar composites. Taking the electrical resistivity of the composites as index, the optimum processing parameters are: forming pressure of 600 MPa, sintering temperature of 1000°C, holding time of 60 min and Cu content of 50 wt-%.