Ti-Al-Zr合金的氢致脆性研究

Study of Hydrogen Induced Embrittlement of Ti-Al-Zr Alloys

为了研究氢进入钛合金试样后对其力学性能的影响,探索氢在钛合金中的行为,本文用电解渗氢方法对Ti-Al-Zr合金进行了渗氢处理,得到了不同含氢量的试样.在室温下进行了试样的拉伸、冲击实验.结果表明,试样渗氢后的强度得到不同程度的提高,这是固溶强化的结果;试样的塑性随氢含量的提高而下降,当氢含量达到～1200μg/g时,塑性损失达到25%;试样的冲击韧性随氢含量的提高而下降,试样中氢含量达到～300μg/g时,冲击韧性下降～80%,试样已基本上呈脆性.使用SEM研究了渗氢样品的断口形貌后发现,拉伸试样中只有少量二次裂纹,而冲击试样有大量二次裂纹产生,并伴有准解理特征.

The tensile and impact tests of the cathodic charging Ti-Al-Zr alloy were measured with the hydrogen concentration up to 1200 μg/g in order to study the behavior of hydrogen in titanium alloys. The results showed that the strength of the alloy had increased and this was the result of solid solution strengthening. The total elongation exhibited a negative dependence on the hydrogen and decreased with the hydrogen monotonically from -30% to 22% in the range. The absorbed energy also exhibited a negative dependence on the hydrogen and decreased by 80% at -300μg/g, which reflected that this alloy had much sensitivity to embrittlernent by hydrogen even in the slight increase of hydrogen content. The fracture characteristics for the tensile and impact specimens were analyzed, and it showed that there existed a lot of large secondary cracks in the impact specimens, and the fracture mode was changed from ductile to cleavage as the hydrogen content increases. However, there only had some small secondary cracks in the tensile specimens.