Effects of Trace Alloying Elements Fe and Cr on the Microstructure and Aging Properties of Cu-3Ti Alloy Foils

In this work, the effects of an addition of trace alloying elements, Fe and Cr, on the mechanical and electrical properties and corrosion resistance of Cu-3Ti alloy foils, have been investigated. The results showed that the individual addition of Fe leads to the formation of Fe2Ti intermetallic phase, which refines the grain size, in the solution-treated condition. With a combined addition of Fe and Cr, the formation of the (FeCr)2Ti phase and the precipitation of the β′-Cu4Ti phase resulted in increased hardness in the peak-aged condition. The ultimate tensile strength and yield strength of the peak-aged Cu-Ti-Fe-Cr alloy were 13% and 5.7% higher, than those of the Cu-3Ti alloy, respectively. The electrical conductivity of the peak-aged Cu-Ti-Fe-Cr alloy was 3.3% higher than that of the Cu-Ti-Fe alloy, due to the finer (FeCr)2Ti phase and the less residual Ti atoms, in the Cu matrix. The combined addition of Fe and Cr elements could improve the corrosion resistance of the Cu-Ti alloy. The Cu-Ti-Fe-Cr alloy foil could obtain the best integrated properties, and the hardness, ultimate tensile strength, and electrical conductivity were 357.1 HV, 1068 MPa and 12.5% IACS, respectively.