Microstructure evolution, mechanical properties and tribological behaviors of copper alloy aged at different temperatures

Abstract To clarify the effect of aging treatment on the microstructure and properties of Cu–3Ti–2Mg alloy, a Cu–3Ti–2Mg alloy ingot was fabricated, followed by homogenizing at 800 °C for 10 h, solubilizing at 750 °C for 4 h and aging at different temperatures. The microstructure was characterized by SEM, EPMA, TEM, 3D laser scanning microscope and Raman spectroscope, and the mechanical properties, electrical conductivity and tribological performance of Cu–3Ti–2Mg alloy was tested. The results showed that the diffraction peaks of Cu gradually shift to the left with increase of the aging temperature, indicating Ti precipitate from the Cu matrix. The interfaces between precipitation phases and Cu matrix exhibit a clean and tight bond without visible defects. With increase of aging temperatures, more Ti precipitated from Cu matrix enhances the electrical conductivity, hardness and elasticity modulus are increased due to the formation of β′-Cu4Ti, β-Cu3Ti and Cu2Mg phase. Friction test indicated that the precipitation strengthening improves the wear resistance of the Cu–3Ti–2Mg alloy and the alloy after aging at 500 °C has the lowest wear rate of 2 × 10−5 g/Nm. The Raman analysis revealed that the tribofilm formed on the wear surface is consisted of Cu2O. Based on the analysis for the mechanical properties and tribological behaviors analysis as the function of the aging temperature of the Cu–3Ti–2Mg alloy, it suggests that the synergistic effect between β′-Cu4Ti phase and Cu2Mg phase endows the possibility for the alloy to be used under the conductive friction service condition.