Effect of titanium addition on the microstructure, electrical conductivity and mechanical properties of copper by using SPS for the preparation of Cu-Ti alloys

Abstract

This study assessed the electrical conductivity and the mechanical properties of pure Cu, 1 and 2.6 mass % Ti additions in a composition of CuTi0.014 and CuTi0.035 in region of Cu-solid solution, with the aim of studying the effect of titanium additions on the properties of copper. A sample of pure Cu, CuTi0.014 and CuTi0.035 were prepared in a plastic canister and mixed with alumina balls for 3 h at 49 rpm. The powdered samples were sintered at a temperature of 650 °C, with a punch load of 50 MPa, a dwelling time of 5 min and a heating rate of 50 °C/min. The results showed that the electrical conductivity of Cu, CuTi0.014 and CuTi0.035 are: 4.8, 5.0 and 4.2 (S/m) at temperatures of 345, 550 and 319 °C, respectively. The relative densities of the sintered samples are 96.76, 96.30 and 86.33% for Cu, CuTi0.014 and CuTi0.035, respectively. The Vickers hardness data of the sintered samples show that CuTi0.035 has the highest value (∼749 MPa), followed by CuTi0.014 (∼724 MPa) and pure Cu with (∼645 MPa). In addition, the predicted yield strength (YS) and ultimate tensile strength (UTS) of the sintered samples were investigated. The YS are 1604, 1552 and 1395 MPa for CuTi0.035, CuTi0.014 and Cu, respectively. In similar other, the UTS are 1318, 1285 and 1182 MPa. The addition of 1 and 2.6 mass % Ti improved the corrosion resistivity of Cu in H2SO4 acid environment. Also, the addition of the 2.6 and mass % of Ti increases the coefficient of friction of Cu under dry sliding condition with a load of 25 N. The microstructures of the sintered CuTi0.014 and CuTi0.035 showed the precipitation of Ti. However, CuTi0.014 alloy has the best properties and is an ideal candidate for elevated temperature application. This composition of CuTi alloys can be used in the areas where Cu is required to maintain good electrical and mechanical properties at elevated temperatures (above room temperature) applications.