Influence of trace additions of titanium on grain characteristics, conductivity and mechanical properties of copper-silicon-titanium alloys

The main objective of this research is to explore the influence of trace additions of titanium on grain characteristics (morphology and size), conductivity, and mechanical properties of copper-silicon-titanium alloys. The alloys compositions were designed using response surface optimal design (RSOD). The designed alloy compositions were melted, cast, and subjected to normalizing heat treatment at 900 °C for 0.5 hr. The grain characteristics and the elemental constituents of the produced alloys were analyzed using an optical microscope (OM), scanning electron microscopy (SEM), and x-ray fluorescence spectroscopy. The average grain size and distribution were also determined. The properties investigated were percentage elongation, tensile strength, hardness, electrical conductivity, and density. The results were analyzed statistically using analysis of variance (ANOVA) to obtain the significance of titanium content on the tested properties and to generate statistical model equations for future applications. The experimental results were optimized to ascertain the optimal alloy composition and properties. The OM and SEM results revealed a decrease in the average grain size of the parent alloy (Cu–3Si) from ≈10.1 μm to ≈4.4 μm and change in grain morphology after adding titanium, leading to improvement of properties. The results were confirmed to be statistically significant. The optimization results revealed Cu–3Si-0.47wt%Ti as the optimal alloy composition.