Improving mechanical property of Ti55531 alloy by yttrium dopant.

Obtaining higher mechanical properties, particularly the coexistence of strength and ductility, is always an important issue for high-strength and high-ductile metastable β titanium alloy, such as Ti55531. Rare earth element doping to gain reticulate structure is a possible way to break the strength-ductility trade-off considering the excellent capability of yttrium in improving the properties of titanium alloys and limiting grain growth. In this study, a new strategy was devised for the preparation of Ti55531 alloys with a reticulate structure by introducing yttrium and a tailored spark plasma sintering (SPS) procedure. Compared to the homogeneous structure, the strength of the material with a reticulate structure is prominently improved at the little expense of loss in ductility. Furthermore, the addition of yttrium can significantly increase the precipitation of α phase by affecting the local element concentration. It is hoped that this study can provide important inspiration for improving the mechanical properties of powder metallurgy fabricated titanium alloys. • Titanium alloys with reticulate structure prepared by doping yttrium and SPS technology. • The Ti55531 alloy with reticulate structure has good strength-ductility matching. • Yttrium affects the microstructure evolution and crack propagation path of Ti55531 alloy. [ABSTRACT FROM AUTHOR]