Influence of chromium addition on the microstructural and mechanical properties of copper-magnesium alloys

Abstract

The study investigated the influence of trace additions of chromium on grain characteristics, electrical conductivity, and mechanical properties of Cu-4wt%Mg alloys. The experimental alloys were produced with various chromium concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0% by weight using the permanent mold casting technique. Tensile, hardness, impact, and conductivity tests were carried out on the cast samples. Microstructures of the specimens were also analyzed using optical microscopy. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were used to characterize the cast specimens. The results showed that adding chromium to Cu-4wt%Mg alloy refined and modified the structure of the alloy, resulting in improvements in the ultimate tensile strength, hardness, and conductivity of the experimental alloy by 31.0%, 33.2%, and 24.7%, respectively, at 0.9wt% Cr content, and percentage elongation, impact strength, and electrical conductivity by 13.48%, 131J, and 32.3Sm-1, respectively, at 0.1wt%Cr content. The addition of chromium also led to the formation of the intermetallic phase which further contributed to the increase in strength and hardness of the alloy.