Selective laser melting of near Ti-5321 β titanium alloy: Microstructure, mechanical properties and deformation mechanism

Abstract

In this work, the microstructure of near β Ti-5321 (Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe) alloy was optimized by varying the parameters of the selective laser melting (SLM) process. The room-temperature tensile properties of the samples were tested, and the deformation mechanism was analyzed. Fully dense sample preparation was achieved by changing the laser power and scanning speed parameters of SLM. The results of electron backscatter diffraction (EBSD) analysis showed that as-depositedsample containe columnar β grains with <001>//BD texture, and the width of the grains increased with the increase of laser power. The total elongation of the Ti-5321 alloy sample reaches 17 % and the ultimate tensile strength is 1126 MPa at room temperature tensile; the presence of α″ phase and {332}< 113> and {112}< 111> deformation twins in the microstructure of the sample near the tensile fracture suggests that the sample contains multiple deformation mechanisms, i.e, dislocation slip, transformation-induced plasticity (TRIP), and twinning-induced plasticity (TWIP).