Effect of energy density on microstructure and mechanical properties of Ta-33Ti alloy prepared via laser powder bed fusion
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Hunan Huaxiang Medical Technology Co., Ltd., Ningxiang 410600, China)
2. Hunan Huaxiang Medical Technology Co., Ltd., Ningxiang 410600, China)
Abstract: The influence of laser process parameters on the densification, phase composition, microstructure, and mechanical properties of Ta-33wt.%Ti alloy prepared via laser powder bed fusion (LPBF) was investigated. The results show that fully dense and homogeneous Ta-Ti parts can be obtained from LPBF with appropriate energy input. The cellular and dendritic structures were formed due to constitutional undercooling. Transmission electron microscopy (TEM) analysis showed that the lamellar α″ phase within the cellular structures preferred to concentrate at the cellular boundaries owing to the elemental micro-segregation in the solidification front. The samples fabricated under the energy density of 166.7 J/mm3 had a favorable ultimate tensile strength of 806 MPa and an excellent Young’s modulus of 36.7 GPa.
Key words: Ta-Ti alloy; laser powder bed fusion; cellular and dendritic structures; constitutional undercooling