氢对锆基块体非晶合金形变和开裂的影响

通过充氢和未充氢缺口拉伸试样和三点弯曲试样在SEM下的原位加载,研究了氢对Zr65Al7.5Ni10Cu17．5块体非晶合金形变和开裂过程的影响．结果表明,无论是否有氢,块体非晶的剪切带发展到临界尺寸,剪切裂纹就沿剪切带形核、扩展,它一旦张开就导致快速的断裂．断口边缘观察到的无特征区是剪切带,而不是剪切裂纹断口;剪切断口形貌和拉伸断口形貌没有本质区别．只有当长时间充氢才能形成氢鼓泡,如鼓泡很小或尚未形成,则氢对剪切带以及裂纹的形核、扩展没有明显影响;如存在较大的氢鼓泡,则当剪切带尚未充分发展时微裂纹就形核,导致低应力脆断．

<span style="color: rgb(0, 0, 0); font-family: verdana, Arial, Helvetica, sans-serif; font-size: 13px;">The effects of hydrogen on shear bands and cracking in bulk amorphous alloy Zr65Al7.5Ni10Cu17.5 have been studied through in situ tensile single-edge notched samples and three-point bending smooth samples in SEM. The results show that for either hydrogen-free or hydrogenated samples, shear crack will initiate and propagate along shear bands when shear bands grow to a critical condition, and open finally, resulting in rapid fracture of samples. The characterless zone on the fracture surface is the shear band instead of fracture surface of shear crack. There is no essential difference between the morphologies of tensile fracture and shear surface. Hydrogen blistering will form after charging for a long time, and if the blistering is very small or unformed, there is no evident effect for forming of shear bands and initiating of crack. If the hydrogen blistering is large enough, the shear crack will initiate at early growing stage of shear band, resulting in brittle fracture under low stress.</span>