Deformation behaviour of Zr-based metallic glass and metallic glass composite at elevated temperatures

在本项目中，将使用TEM研究Zr55Cu30Ni5Al10整体大块金属玻璃的详细纳米化情况，并与之前两种样品在高应变率和高温下变形后退火得到的部分纳米化Zr55Cu30Ni5Al10大块金属玻璃进行比较。通过对不同类型样品的比较，可以了解纳米化对高温变形行为的影响，以及新纳米化相与先前退火获得的部分纳米化相之间的反应从不均匀到均匀流动的转变。此外，优化具有延展性枝晶的Zr66.4Cu10.5Ni8.7Al8块状金属玻璃复合材料的铸造条件，以控制和建立不同枝晶的长度尺度和体积分数，从而了解枝晶的形貌和体积分数对不同应变速率和高温下顺滑流动的影响。最后，系统地研究和比较了整体块体金属玻璃、部分纳米化块体金属玻璃和具有韧性相的块体金属玻璃复合材料的高温变形行为。这也将有助于理解非晶相、纳米晶体和微米级枝晶之间剪切带的产生、运动和相互作用

In this project, the detailed nanocrytallization of the Zr55Cu30Ni5Al10 monolithic bulk metallic glass will be investigated using TEM in comparison with that of the partially nanocrystallized Zr55Cu30Ni5Al10 bulk metallic glass obtained by previous annealing after the deformation of both types of samples at high strain rates and at elevated temperatures. The comparison of the different types of samples allows to understand the effect of the nanocrystallization on the high temperature deformation behaviour and the transitionfrom inhomogeneous to homogeneous flow regarding the reaction between the newly nanocrystallized phase and the partially nanocrystallized phase obtained by previous annealing. In addition, it is of interest to optimize the casting conditions of the Zr66.4Cu10.5Ni8.7Al8 bulk metallic glass composite with ductile dendrites in order to control and establish a different lenght scale and volume fraction of dendrites, and hence to understand the effect of the morphology and the volume fraction of the dendrites, on the ciscous flow at various strain rates and at elevated temperatures. Finally, the deformation behavior at elevated temperatures between monolithic bulk metallic glass, partially nanocrystallized bulk metallic glass and bulk metallic glass composite with ductile phase will be systematically investigated and compared. This will be also helpful to understand the generation, movement and interaction of shear bands between the amorphous phase, the nanocrystals, and the micrometer- sized dendrites