ZrCuNiAl块体非晶合金的低温压缩变形行为

Compressive deformation behavior of ZrCuNiAl bulk metallic glass at low temperature

采用Instron 5500万能试验机对Zr_(55.7)Cu_(23)Ni_9Al_(12.3)块体非晶合金进行了应变速率为4×10^(-4)s^(-1)、环境温度为143 K的低温压缩试验,研究了其低温压缩变形行为。结果表明,当测试环境温度从298 K(室温)降低到143 K时,该合金的强度和塑性均呈增加的趋势,且未出现传统晶态材料的冷脆性现象。分析表明,其屈服强度的增加源于低温下剪切带的形核需要更高的载荷,而低温下断口侧面高密度剪切带的形成导致了其塑性的增加。

Low temperature compression tests for the Zr_（55. 7）Cu_（23）Ni_9Al_（12. 3） bulk metallic glass（ BMG） were carried out at the strain rate of 4 ×10^（-4）s^（-1） and at the temperature of 143 K on Instron 5500 universal-testing machine,and the compressive deformation behavior of the Zr_（55. 7）Cu_（23）Ni_9Al_（12. 3）BMG during low temperature compression was investigated. The results show that the compressive yield strength and plasticity of the Zr_（55. 7）Cu_（23）Ni_9Al_（12. 3）BMG improve as testing temperature decreasing from 298 K to 143 K. Meanwhile,the phenomenon of ductile-to-brittle transition（ DBT） in traditional crystalline material is not observed with the decrease of temperature. The increase of yield strength is attributed to the nucleation of shear bands which requires a higher applied load at low temperature. Dense and multiple shear bands which are contributed to the enhanced ductility are observed on the side surface of the low temperature fractured samples.