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对了Ti_3Al+Nb金属间化合物,用预裂纹试样研究原子氢引起的氢致开裂。结果表明,无论在室温还是高温(400℃),氢能促进局部塑性变形。当它发展到临界状态时,氢致裂纹就在塑性区中某一特征位置处沿滑移带形核。研究了氢作为暂时合金元素对氢致开裂门槛值K_(IH)和断裂韧性K_(IC)的影响。还研究了氢化物含量对氢致开裂门槛值K_(IH)的影响。根据氢促进局部塑性变形从而促进解理断裂的理论导出了K_(IH)的定量表达式。
For the Ti_3Al + Nb intermetallics, hydrogen cracking induced by atomic hydrogen was studied using a pre-cracked specimen. The results show that hydrogen can promote local plastic deformation at room temperature or high temperature (400 ℃). As it progresses to a critical state, the hydrogen-induced crack slips along the nucleation zone at a certain characteristic location in the plastic zone. The effects of hydrogen as a temporary alloying element on the hydrogen induced cracking threshold K_ (IH) and fracture toughness K_ (IC) were studied. The effect of hydride content on the hydrogen cracking threshold K_ (IH) was also studied. According to the theory that hydrogen promotes local plastic deformation and promotes cleavage fracture, the quantitative expression of K_ (IH) is deduced.