Ti6Al4V合金精铸件疲劳性能试验研究

Experimental Research on Fatigue Behaviour of Ti6Al4V Precision Casting

采用Ti6Al4V合金精密铸件解剖后加工的方法,进行了400MPa、460MPa和520MPa三种不同应力水平下的疲劳性能试验研究。疲劳试验载荷采用三角波和轴向循环加载,加载系数K=0.4,应力比R=0.1,且在等幅应力下进行。结果表明,400MPa应力水平下,铸造Ti6Al4V合金疲劳寿命能达到106周次。但是随着应力水平的提高,疲劳寿命急剧下降且数据分散性大。断口观察和分析显示,疲劳源区不同类型的缺陷,是影响合金疲劳性能的主要原因。

The fatigue properties of Ti6Al4V precision casting under 400 MPa, 460 MPa and 520 MPa were studied. Triangular wave and axial circulating load were applied in constant- amplitude test with the loading coefficient K = 0.4 and stress ratio R= 0.1. The results show that the fatigue life of Ti6Al4V casting could reach 106 cycles under the stress of 400 MPa, but it decreases sharply and become dispersive with the increase of stress level. The fracture analysis shows that the main reason to affect fatigue property is the various defects in the zone of fatigue source.