弯折次数对Ti-Cu基非晶合金剪切带扩展的影响

Effect of Bending Times on the Propagation of Shear Band in Ti-Cu Amorphous Alloy

通过快速凝固技术制备了Ti_(36.89)Cu_(43.87)Ni_(9.36)Zr_(9.88)非晶合金薄带,对非晶合金薄带进行了1次、3次和5次弯折且折断,研究弯折次数对剪切带扩展的影响。利用扫描电子显微镜对折断后薄带的剪切带及断口进行了研究。结果表明,一次弯折剪切带只在拉应力作用下,交叉剪切带较少,剪切带相互作用较弱,剪切带之间趋向于独立形核并进行扩展;3次弯折剪切带在交变应力作用下,多个剪切带相互交叉,剪切带之间的相互作用较强,且少量的剪切带可以独立形核或扩展;5次弯折剪切带受交变应力,离断口较近剪切带部分形成裂纹,剪切带相互交叉较少,剪切带相互作用较弱,断口存在韧窝形貌。

The Ti36.89CU43.89NI9.36ZR9.88 amorphous ribbons were prepared by rapid solidification processing. The amorphous ribbons were bent one, three, and five times broken. The influence of bending times on the propagation of shear band was studied. The shear bands and fracture were investigated by scanning electron microscope. The results show that the shear band at the one bending is only under tensile stress, and the cross of shear band is less. The interaction of shear bands is weak, and the shear bands tend to nucleate independently and to propagate. The shear band at three bending is under the action of alternating stress, the cross of multiple shear bands occurs, the interaction between shear bands become stronger, compared with the shear band at one bending, and a small number of shear bands can nucleate independently or propagate. The shear bands at five bending subjects to alternating stress, the cracks form in the shear zone near the fracture surface, the cross between shear bands is less, and the interaction is weak. In addition, the dimple is found in fracture morphology.