民用航空发动机TA19电子束焊疲劳试验

针对民用航空发动机钛合金整体叶盘常用材料TA19开展其母材试件与电子束焊焊接试件在20,300,450℃的疲劳试验,通过焊接试件的焊缝材料断口与母材断口形貌的比较探讨了焊缝材料的疲劳破坏机理,并在104~106循环的疲劳寿命区间内采用Basquin模型分别建立了焊缝材料和母材的应力-疲劳寿命(S-N)曲线,结果显示母材试件与焊接试件的试验疲劳寿命大部分都落在了对应模型计算疲劳寿命的2倍线之内,表明试验得到的S-N曲线是合理的.焊接试件与母材试件的S-N曲线的对比分析表明,20℃时焊接试件的疲劳性能比母材试件略高,而在300℃和450℃时焊接试件与母材试件的疲劳性能差异随应力水平发生变化.但总地说来,在所关注疲劳寿命区间内,母材试件与焊接试件的计算疲劳寿命差异也在2倍线以内,初步表明两者的疲劳性能相当. 

Fatigue test of electron beam welding for TA19 in civil aircraft engine

Fatigue test for welding specimen of electron beam welding and base metal specimen of TA19, which was made of titanium-based alloy often used in the blisk of civil aircraft engine, was performed at temperature 20, 300, 450℃. Fracture mechanism of welded joint was discussed by comparing the fracture face microstructures of welded metal with that of base metal. Then the stress-fatigue life (S-N) curves of both base metal and welded metal were created based on Basquin model in the fatigue life range of 104 to 106 cycles, showing that few test data of fatigue life can go beyond the two times error margin in the corresponding models, which indicates that the S-N curve obtained by test is reasonable. Through comparison of the S-N curves of welding specimen and base metal specimen, it can be seen that fatigue performance of welding specimen is higher than that of base metal specimen at temperature 20℃, while the differences of the fatigue performance between welding specimen and base metal specimen vary with the stress amplitude at temperature 300℃ and 450℃. Also, in above fatigue life range, the differences of calculated life prediction for welding specimen and base metal specimen are within the two times error margin. Thereby, the conclusion can be drawn that the fatigue performances of both are closer.