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采用变截面薄板试样,研究了4种氢含量对Ti-4Al-2V钛合金疲劳寿命的影响。研究结果表明:当拉伸疲劳载荷Dσ大于550MPa时,充氢材料的疲劳寿命高于自然含氢量的材料;在高的Dσ下,含氢量在116~280μg·g-1范围内变化时,对Ti-4Al-2V的寿命影响较小;Dσ降低后,氢含量越高,疲劳寿命越低,同时,Dσ的大小会影响疲劳裂纹的萌生位置。可以认为:材料中固溶氢和氢化物对驻留滑移带(PSB)的影响降低了充氢试样的疲劳裂纹萌生寿命,而高含氢量的Ti-4Al-2V材料在裂纹尖端,通过应力诱导析出氢化物,使裂纹扩展寿命降低。
The effects of four kinds of hydrogen content on the fatigue life of Ti-4Al-2V titanium alloy were studied by using the specimens with variable cross-section. The results show that when the tensile fatigue load Dσ is greater than 550MPa, the fatigue life of the hydrogen-filled material is higher than that of the natural hydrogen-containing material. Under high Dσ, the hydrogen content changes in the range of 116 ~ 280μg · g-1 , Which has little effect on the life of Ti-4Al-2V. After the decrease of Dσ, the higher the hydrogen content, the lower the fatigue life. At the same time, the size of Dσ will affect the initiation of fatigue crack initiation. It can be considered that the effect of dissolved hydrogen and hydride on the resident slip band (PSB) reduces the fatigue crack initiation life of the hydrogen-filled sample, while the high hydrogen content of Ti-4Al-2V material at the crack tip, Hydrides are induced by stress-induced reduction of the life of the crack propagation.