Insight into the microstructure and mechanical properties of Cu-20wt%Zn-xSn ternary alloy

The main objective of this research is to study the grain refinement and improved trend in mechanical properties of brass (Cu-20wt%Zn) doped with tin. Tin was added in concentrations of (x: 0.1, 0.3, 0.5, 0.8, and 1wt%). The alloy samples were produced by permanent die casting and machined to the required dimensions for the structural analysis and mechanical tests. Mechanical properties studied were percentage elongation, ultimate tensile strength, and Brinell hardness using a 100KN JPL tensile strength tester (Model: 130812) and portable dynamic hardness testing machine (Model: DHT-6) respectively. The structural analysis was conducted using an optical metallurgical microscope (Model: L2003A) and scanning electron microscopy (SEM) equipped with EDS. The results of the structural analysis showed that the control specimen consisted predominantly of coarse α-phase of zinc in copper (Cu3Zn). The samples doped with tin consisted of refined α-grains with patches of the second phase (Cu8Sn5). Mechanical test results indicated that the addition of tin to alpha brass improved the ultimate tensile strength and hardness with a slight decline in percentage elongation. The values recorded for ultimate tensile strength and Brinell hardness were 322MPa and 176HB respectively.