Dependence of mechanical properties on the microstructure characteristics of a near β titanium alloy Ti-7333

Abstract

In this work, the microstructure and the corresponding tensile properties of the rolled Ti-7Mo-3Nb-3Cr-3Al (Ti-7333) alloy before and after the thermal treatments were investigated. The results show that a strong α-fiber texture is developed in the rolled Ti-7333 alloy. The deformed matrix and the texture significantly induce the variant selection of α phase. The high strength of the rolled Ti-7333 alloy is attributed to the <110> texture parallel to the tensile direction and the dispersed α phase within the matrix. After the solution treatment followed by the aging treatment, the texture decreases and the microstructure consists of the equiaxed β grains, the spheroidal αp phase and various needle-like α variants. Eventually, the alloy could achieve an optimal combination with the strength of about 1450 MPa, the ductility of about 10.5% and a considerable shear strength of about 775 MPa. This balance can be ascribed to the performance of the spheroidal αp phase and various needle-like αs variants. The results indicate that the Ti-7333 alloy could be a promising candidate material for the high-strength fastener.