A Processing Route for Achieving Isotropic Tensile Properties in Laser Solid Formed α + β Titanium Alloy

A two-step processing route for achieving isotropic tensile properties in laser solid formed (LSF) α+β titanium alloy is proposed. Titanium alloy parts containing equiaxed prior β grains and relative homogeneous α laths were obtained by adjusting the LSF processing parameters and the post heat treatment conditions, respectively. The microstructure and texture characteristics of the LSFed titanium alloy under different heat treatment conditions were investigated. The room temperature tensile tests were performed at various loaded angles with respect to the building direction. The results showed that the prior β grains are close to isotropic both in morphology and texture. The scale and volume fraction of the α laths vary with the heat treatment conditions. The tensile properties are anisotropic after the aging treatment, while the tensile properties are isotropic after the solution + aging treatments. The fracture surface and microstructure analysis indicated that the anisotropy in the tensile properties is directly related to the heterogeneous α laths in the aging-treated specimens. The isotropic tensile properties in the LSFed titanium alloys could be achieved by adopting the processing route proposed in the present study.