Crystallization behavior of Ti3Al-Nb alloy laser beam welding joints
(1.黑龙江省哈尔滨市哈尔滨工业大学现代焊接生产技术国家重点实验室2.State Key Laboratory of Advanced Welding Production Technology,Harbin Institute of Technology, Harbin 150001, China3.State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 15001, China)
Abstract: CO2 laser beam welding experiment of Ti3Al-Nb alloy was conducted by adopting overlay welding, the resulting special crystallization phenomenon of welding joint was analyzed. The joints have obvious crystallizing layer phenomenon with clear bond-like contours after laser welding. The results of X-spectrofluorimetry and energy spectrum analysis indicate that the non-uniform distribution of elements exists in crystallizing layer, because the temperature gradient is an important factor that impacts the alloy crystallization behavior. Furthermore, the effects of welding heat source, welding speed, pulse frequency and welding preheat on crystallizing layer distribution were investigated.
Key words: Ti3Al-Nb alloy； laser welding； crystallizing layer； crystallization behavior