The microstructure and mechanical behaviors of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy produced by laser melting deposition

The microstructure and mechanical properties of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy produced by laser melting deposition have been investigated. The columnar grains of the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy due to the layer-by-layer epitaxial growth from the underlying template grains during laser melting deposition, which is roughly parallel to the deposition direction, had been found by optical microscopy; strong 10 1 ¯ 2 α crystallographic texture has been confirmed by X-ray diffraction and electron backscattered diffraction. Depending on the last heating history, the microstructure of the alloy undergoes a continued change opposite to the deposition direction: martensitic α′ (transformed β); coarsened primary α laths with transformed β; coarsened primary α laths; and the fine basketweave microstructure with a few coarsened α laths or annealed martensitic α′. The average Vickers micro-hardness value of the alloy is 364 HV. The alloy parallel to the deposition direction presents lower tensile strength (925 MPa) and better elongation (18.8%), compared with 1025 MPa and 8.2% of that vertical to the deposition direction, which has been discussed using its microstructure characterization.