Microstructure, texture and tensile properties as a function of laser power of Ti48Al2Cr2Nb5Ta alloy prepared by laser additive manufacturing

Abstract

The microstructure, phase composition, texture, and tensile properties of Ti48Al2Cr2Nb5Ta alloy prepared by laser additive manufacturing (LAM) were all investigated in detail. The microstructure of the alloy is constituted of α2(Ti3Al), γ(TiAl), and β/B2 (β ordered to B2) phases, according to the results. The microstructure changes from lamellar structure to lamellar structure divided by massive β/B2 phase when the laser power increases from 1.0 kW to 2.2 kW. Furthermore, when the laser power is 2.2 kW, the content of the β/B2 phase achieves its highest value (9.43%), whereas when the laser power is 1.8 kW, the content of the α2 phase reaches its maximum value (9.43%). The crystal texture of the γ(111) and α2(0001) orientations strengthens as laser power increases. Tensile characteristics demonstrate that the 1.4 kW alloy has the best tensile strength and elongation at room temperature and 750 °C, with values of 677 MPa, 651 MPa, and 1.8%, 2.2%, respectively. However, when compared to other alloys, the 1.4 kW alloy's tensile strength and elongation at 850 °C are slightly lower (538 MPa 13%).