Effects of Hydrogen on Shear Bands and Cracking in Zr Base Bulk Amorphous Alloy
氢对锆基块体非晶合金形变和开裂的影响

The effects of hydrogen on shear bands and cracking in bulk amorphous alloy Zr65Al7.5Ni10Cu17.5 have been studied through in situ tensile singlc cdge notched samples and threepoint 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.