Effect of the rare earth element Ce on the microstructure, properties and thermal stability of Cu-5Fe alloy

Abstract

The effect of the rare earth element Ce on the morphology evolution, mechanical properties, and thermal stability of the Fe phase in the Cu-5Fe alloy was investigated. Experimental results demonstrate that adding Ce to the Cu-5Fe alloy significantly improves its comprehensive properties, with the tensile strength of the Cu-5Fe-0.1Ce alloy reaching 534 MPa and the electrical conductivity reaching 71% IACS after aging at 350 °C for 1 h. Compared to the Cu-5Fe alloy, the tensile strength experienced an increment of 93 MPa, while the electrical conductivity decreased only by about 2% IACS. The addition of Ce promotes the precipitation of the primary Fe phase, refines the Fe phase, and increases the density of Fe fibers, resulting in excellent mechanical properties. In addition, the thermal stability and grooving kinetics of Fe fibers were assessed. The primary mechanism of Fe fiber structural instability is the thermally-induced grooving at a triple junction where the grain boundary meets the Cu/Fe phase interface. The Fe phase is more likely to form thermally induced grooves and fractures during the aging process due to its high grain boundary energy. Adding Ce to the alloy slows down the expansion of grooves, playing a role in improving the thermal stability of the alloy.