2019 Volume 60 Issue 9 Pages 1749-1754
The effect of Si addition on the microstructure and mechanical properties of a near-β titanium alloy Ti-17 with fully lamella microstructure was investigated. It was found that the microstructure of Ti-17 with silicon exhibited the absence of a continuously thick α layer along prior-β grain boundaries (grain boundary α), while the grain boundary α was distinctively formed in Ti-17 without Si. The formation of (Ti, Zr) silicide particles at the prior-β grain interior and its grain boundaries were observed, and the presence of these particles were related to the disappearance of grain boundary α similar to the oxygen scavenging effect of boride particles reported previously. With regard to mechanical properties, Ti-17 with silicon exhibits higher strength and lower ductility compared with Ti-17 without Si. Ductile transgranular fracture morphology was observed even on the fracture surface of Ti-17 with Si after tensile test.
