Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metasta...Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metastable β-phase during aging.The results show that the ordered primary α_2 and high temperature β in alloy form at 1060℃.The transformation of high temperature β-phase proceed by β→α_2+ω type during cooling,and the decomposition of metastable β and ω type proceeded by(β+ω)_(metustabte)→(α_2+β)_(stable)during aging at 700℃.展开更多
Ti_3Al+Si+Nb alloys containing Ti_5Si_3 have the potential in ductility improvements. In this paper, the fracture mechanism of this alloy is under investigation. Three kinds of alloys in the as rolled condition were p...Ti_3Al+Si+Nb alloys containing Ti_5Si_3 have the potential in ductility improvements. In this paper, the fracture mechanism of this alloy is under investigation. Three kinds of alloys in the as rolled condition were prepared for determination of KIC values and calculation of J-resistance curves. The results show that the morphology of Ti_5Si_3 has a great influence on the KIC. values of the alloys and crack growth resistance. The fracture mechanism is controlled by Ti_5Si_3 particles.展开更多
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 laye...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.展开更多
文摘Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metastable β-phase during aging.The results show that the ordered primary α_2 and high temperature β in alloy form at 1060℃.The transformation of high temperature β-phase proceed by β→α_2+ω type during cooling,and the decomposition of metastable β and ω type proceeded by(β+ω)_(metustabte)→(α_2+β)_(stable)during aging at 700℃.
文摘Ti_3Al+Si+Nb alloys containing Ti_5Si_3 have the potential in ductility improvements. In this paper, the fracture mechanism of this alloy is under investigation. Three kinds of alloys in the as rolled condition were prepared for determination of KIC values and calculation of J-resistance curves. The results show that the morphology of Ti_5Si_3 has a great influence on the KIC. values of the alloys and crack growth resistance. The fracture mechanism is controlled by Ti_5Si_3 particles.
文摘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.
