高応力比を及ぼす「高じん性」Zr₅₅Al₁₀Ni₅Cu₃₀金属ガラスの疲労破壊進展挙動

抄録

Bulk Metallic Glasses (BMGs) hold a noticeable attention in the scientific community. This type of material exhibits indeed very interesting properties, such as high strength, noticeable elongation at fracture and good corrosion resistance. However, it is common knowledge that BMGs show poor fatigue resistance, such as present usage of BMGs is restricted to non-structural applications. In order to grasp the complexity surrounding the fatigue loading, the present study investigates the effect of the stress ratio R (= σ_min / σ_max) up to high value of R = 0.7.

Such a high stress ratio induced some typical irregularities on the fatigue crack propagation of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG. Indeed, the fracture surface displayed a very peculiar feature, which consists of peak and valley radiating from the crack initiation site. Due to its geometry, this feature is called “gutter-like” pattern. In addition, some other particularities were also observed on the tensile surface of failed specimen