论文标题
剪切束气态确定金属玻璃的应力应变曲线的形状
Shear-band cavitation determines the shape of the stress-strain curve of metallic glasses
论文作者
论文摘要
已知金属眼镜具有非常强大的屈服强度，承认Weibull Moduli与晶体工程合金一样高。然而，它们的产后行为发生了强烈的变化，在两个流动应力水平和失败时菌株中的散射较大。使用X射线层析成像，我们首次揭示了剪切带腔的应变依赖性内部演变是这种不可预测的后产生响应的基础。我们证明了宏观施加量的应变如何与首次检测到内部剪切束气蚀相吻合。发现塑料流期间的腔体生长遵循幂律，该幂律产生了分形维度和粗糙度指数，与裂缝后获得的自相似表面特性非常吻合。这些发现表明，内部微裂缝如何沿应力 - 应变曲线的塑料部分具有剪切带可塑性，合理化了金属玻璃的塑性流动行为的较大可变性。
Metallic glasses are known to have a remarkably robust yield strength, admitting Weibull moduli as high as for crystalline engineering alloys. However, their post-yielding behavior is strongly varying, with large scatter in both flow stress levels and strains at failure. Using x-ray tomography we reveal for the first time how a strain-dependent internal evolution of shear-band cavities underlies this unpredictable post yielding response. We demonstrate how macroscopic strain-softening coincides with the first detection of internal shear-band cavitation. Cavity growth during plastic flow is found to follow a power-law, which yields a fractal dimension and a roughness exponent in excellent agreement with self-similar surface properties obtained after fracture. These findings demonstrate how internal micro-cracking coexists with shear-band plasticity along the plastic part of a stress-strain curve, rationalizing the large variability of plastic flow behavior seen for metallic glasses.
