Effect of strain rate on fracture reliability of Cu45Zr45Co10 amorphous alloy microwires by statistical analyses

摘要

The understanding of the fracture mechanism of amorphous alloys (AAs) is of importance for their engineering applications as advanced structural materials. In this study, a series of micro-tensions of Cu45Zr45Co10 AA microwires were conducted under different strain rates ranging from 5 x 10(-5) s(-1) to 1 x 10(-2) s(-1). It is found that all microwires fracture by shear cracking, but the shear fracture strengths exhibit pronounced rate-dependent uncertainties. Based on both lognormal and Weibull statistical analyses, the studied AA microwires reveal a positive rate-sensitivity of fracture strengths. However, increasing strain rates incurs the decrease in the fracture reliability. We demonstrate that the fracture reliability of AA microwires is dominated by a square root singularity of the characteristic lengths of shear offset on fracture surfaces, which satisfies linear elastic fracture mechanics.

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