影响金属玻璃中剪切带行为的微观机制

论文对金属玻璃发生剪切失稳形成剪切带的行为进行了分析,得到了其发生剪切失稳时的临界自由体积浓度,预测结果与实验观察和模拟结果吻合;利用两种方法对其剪切带厚度进行了预测,结果表明基于剪切失稳临界波长预测金属玻璃剪切带厚度的方法只在发生剪切失稳后极短的时间内有效,对成熟剪切带厚度的预测必须考虑自由体积的扩散效应;考察了金属玻璃的宏微观材料参数对其剪切带厚度的影响及其微观机制,发现金属玻璃剪切带厚度对其宏观材料参数(泊松比)不敏感,对与剪切相变区相关的微结构参数敏感.

MICROMECHANISM OF AFFECTING THE SHEAR BANDING BEHAVIORS IN METALLIC GLASSES

Shear banding behaviors in metallic glasses(MGs) are studied in the present paper.Based on the band-like solution and the critical wavelength of shear banding instability,the critical free volume concentration of shear banding instability and the thickness of shear band in MGs are predicted.The results agree well with experimental observations and simulations.We also demonstrates that the prediction of shear band thickness,which is based on the critical wavelength,is only valid for a short time after shear instability and the diffusion of defects should be included in the mature shear band in MGs.The physical factors governing the thickness of shear bands are also illustrated.The results indicate that the thickness of shear bands is insensitive to the Poison’s ratio and is governed by the features and evolution of the defects.