The effect of hydrogen charging, ultrasonic treatment, and hydrogen charging after ultrasonic treatment on the fatigue life of VT6 alloy is investigated. Ultrasonic treatment causes the formation of a continuous nonetching α2(Ti3Al) layer within the surface layer, which reduces the fatigue life. Below this layer there are bands of the α2(Ti3Al) phase which, on the contrary, increase the fatigue life. These two effects together give a 1.3-fold increase in the fatigue life of the alloy. A catastrophic decrease in hydrogen charging after ultrasonic treatment is explained by the formation of regions of short-range displacements with a bcc lattice similar to the β phase. As a result of radial shear rolling, a martensitic phase with very high strength is formed in the alloy. Its formation is predicted by positron annihilation spectroscopy and is detected by transmission electron microscopy. The high stability of the martensitic phase contributes to the lower fracture toughness of the alloy processed by radial shear rolling.

中文翻译：

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Ti-6Al-4V钛合金晶格曲率对其疲劳寿命和断裂韧性的影响

研究了充氢、超声处理和超声处理后充氢对VT6合金疲劳寿命的影响。超声波处理会导致在表面层内形成连续的非蚀刻 α2(Ti3Al) 层，从而降低疲劳寿命。在该层之下有 α2(Ti3Al) 相带，相反，它们增加了疲劳寿命。这两种效应共同使合金的疲劳寿命增加了 1.3 倍。超声处理后氢充电的灾难性减少可以通过形成具有类似于 β 相的 bcc 晶格的短程位移区域来解释。由于径向剪切轧制，合金中形成了具有非常高强度的马氏体相。它的形成是由正电子湮没光谱预测的，并由透射电子显微镜检测。马氏体相的高稳定性有助于通过径向剪切轧制加工的合金具有较低的断裂韧性。