Heat Accumulation, Microstructure Evolution, and Stress Distribution of Ti–Al Alloy Manufactured by Twin‐Wire Plasma Arc Additive
Xiaoqi Hou, Xin Ye, Xiaoyan Qian, Xi Zhang, Peilei Zhang, Qinghua Lu, Zhishui Yu, Chen Shen, Lin Wang, Xueming Hua
Abstract
Herein, the deposition of a Ti–Al(48 at%) alloy via twin‐wire arc additive manufacturing (WAAM) using plasma arc welding (PAW) and tungsten inert gas (TIG) welding arc sources is presented. The microstructure and the phase composition of different regions of the alloy are analyzed using metalloscopy and X‐ray diffraction. The transient temperature field and residual stress distribution are measured before and after the process, respectively. A transient thermostress model is established using the finite‐element method. Results show that the alloy is composed primarily of α 2 ‐Ti 3 Al and γ‐TiAl phases, while the microstructure evolution during the Ti–Al(48 at%) alloy deposition process is described. The thermal conductivity in the lower region of the alloy far exceeds that in the middle and upper regions. The thermal conductivity is smaller in the upper region and the midregion, resulting in the increase in heat accumulation. Due to arc shrinkage and reduced heat input, the PAW process reduces the heat accumulation and stress distribution differences more effectively than the TIG process.