Effect of Size and Aspect Ratio on the Mechanical Properties of ZrAlNiCuNb Metallic Glass

摘要:

采用单轴压缩和扫描电镜研究试样尺寸和形状因子（长径比）对Zr56Al10.9Ni4.6Cu27.8Nb0.7 金属玻璃力学性能的影响。结果表明，小尺寸和低长径比的金属玻璃试样展现出更好的塑性，主要是小尺寸试样在凝固过程中由于更高的冷却速率而形成了大量的自由体积，以及多重剪切带的稳定传播。同时引入剪切带不稳定因子（SBI）解释了试样尺寸和高径比对金属玻璃塑性的影响。研究表明，小尺寸和低长径比的试样可以获得剪切带的稳定传播，导致金属玻璃基于尺寸和长径比的塑性演变。

Abstract:

The effects of size and aspect ratio (height/diameter ratio) of the specimen on the mechanical properties of a Zr56Al10.9Ni4.6Cu27.8Nb0.7 metallic glass have been investigated by uniaxial compression tests and scanning electron microscope (SEM) observations. The results show that the metallic glass with smaller size and lower aspect ratio shows an enhanced plasticity due to larger amount of free volume formed during casting. The shear-band instability index (SBI) is introduced to explain the effects of the size and aspect ratio on the plasticity of the metallic glass. Stable propagation of shear bands can be achieved for the specimen with small size and low aspect ratio, resulting in a size and aspect ratio dependance of plasticity