Numerical and experimental investigation of laser additive manufactured Ti2AlNb-based alloy

Laser additive manufacturing (LAM) technology was applied to prepare Ti-22Al-25Nb thin-wall sample, and the relationship among thermal history, microstructure and mechanical properties was investigated through simulation and experimental methods. A three-dimensional finite element model was proposed to study the thermal histories of deposited materials during LAM process, combined with the microstructure analysis, microhardness and tensile properties measurements. The simulation results indicated that the thermal history at each location was comprised of successive thermal cycles within different temperature range, which caused the formation of distinct microstructure regions. The microhardness distribution along the deposition direction exhibited the change trend from high to low, associated with the microstructure evolution: B2 + O + alpha(2) -> B2. The deposited materials that close to the substrate possessed the best tensile properties. (C) 2017 Elsevier B.V. All rights reserved.