氢对 Ll_2 结构 Al_(67)Ti_(25)Mn_8 金属间化合物力学性能的影响

Hydrogen Induced Embrittlement of Ll 2 Structured Al 67 Ti 25 Mn 8 Alloy

研究了电解充氢对Ｌｌ２结构Ａｌ６７Ｔｉ２５Ｍｎ８金属间化合物力学性能的影响．结果表明，在压缩试验条件下，充氢不改变材料的屈服强度，但断裂强度及塑性却明显降低．通过断口分析，发现在三点弯曲的起裂边缘存在沿晶断裂的薄层，而在断口内部则基本仍为解理断裂．试样表面沿晶界开裂，并在晶界附近出现浮凸粒子．能谱分析表明为Ｔｉ富集的新相，经热力学分析应为Ｔｉ－Ｈ化合物．表明氢在晶界富集促进了晶间起裂，致使材料的强度和塑性下降．

The effect of hydrogen on the mechanical properties of Al 67 Ti 25 Mn 8 alloy is investigated. The results show that hydrogen precharging does not affect its yield strength in compression, but the fracture strength and ductility decrease obviously. The intergranular fracture is observed mainly in a narrow area with 15￣20 μm depth from the surface of three point bending specimen at the tensile stressed side. Also at this side, the intergranular secondary cracking and small Ti H phase particles (reliefs) exist, suggesting that the hydrogen weakens the grain boundary cohesion and results in the early initiation of cracking.