Influence of Cold Deformation and Aging Heat Treatment on Microstructure and Mechanical Property of TB9 Titanium Alloy

The properties of titanium alloys can be improved by cold deformation and aging heat treatment. However, there are limited reports on the performance transformation of titanium alloys under the combination of cold deformation and aging heat treatment. In this work, the influence of prior cold deformation and the subsequent aging heat treatment on the phase types, a precipitation behaviors and the tensile properties of TB9 titanium alloy were studied by the X-ray diffraction, optical microstructure, scanning electron microscope and uniaxial tensile. The results show that longitudinal and cross section of the bars form different type macro textures through produced different microstructures and affect the microhardness. TB9 titanium alloy is consisted of alpha and beta phases after aging heat treatment. With the increase of the cold deformation rate, the tensile strength is increased and the ductile is reduced. Due to the defects during the cold deformation process, the precipitation free zones disappear in cold deformation samples and the maximum tensile strength reaches 1809 MPa with an elongation of 4%.