Effects of Cu addition on the microstructure and mechanical properties of Ti15Sn alloys

This study investigated the effects of Cu addition on the microstructure and mechanical properties of Ti15SnxCu (x=0 and 2 wt%) alloys. The microstructures were characterized by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate that adding Cu can produced significant grain refinement and mechanical strengthening effects in Ti15SnxCu alloy. The martensitic basket-weave microstructure of Ti15Sn alloy consists of supersaturated α′/α-Ti(Sn) solid solution and nano-Ti3Sn phase. After the addition of 2 wt% Cu, the microstructure of Ti15SnxCu alloy displayed a predo-dendrite structure and plate-like nano-(Ti, Sn)2Cu phase precipitated in α'-Ti(Sn,Cu) lathes. The UTS and YS of the Ti15SnxCu increased, likely due to the refinement of the cellular grain size and lamellar thickness and length, solid solution hardening, and precipitation of nano-(Ti, Sn)2Cu.