Defornation mechanisms in the nanolamellar composite Cu-Nb

纳米层状金属复合材料的塑性行为和微观结构稳定性对实际应用至关重要，因为大多数有益的机械性能与材料中长度尺度的减小有关（即层厚度，层中的晶粒尺寸）。选择不同层厚度为1000 ~ 10 nm的Cu/Nb模型体系，通过低温拉伸试验（包括4k试验）研究其力学性能。基于温度和应变速率变化测试，热激活分析用于确定晶粒尺寸（或更确切地说是层厚度）对实验中测量的总应力的非热影响，从而可以精确分析Hall-Petch关系。此外，热活化分析结果的基本变形机制的信息主导的塑性行为的材料。此外，还研究了温度对变形局部化的影响，通过层内和层间边界的微观和宏观剪切带的发展。变形局部化的程度和影响将通过电子显微镜分析。

The plastic behaviour and microstructural stability of nanolamellar metallic composites are of paramount importance for practical applications since most of the beneficial mechanical properties are related to the diminished length scales (i.e. layer thickness, grain size in the layers) in the material. The model system Cu/Nb produced with different layer thicknesses of 1000 - 10 nm is chosen for investigations of the mechanical properties by tensile tests at low temperatures including 4 K tests. Based on temperature and strain rate change tests thermal activation analysis is used to determine the athermal influence of grain size (or rather layer thickness) on the total stress measured in the experiment allowing a precise analysis of the Hall-Petch relationship. Moreover, thermal activation analysis results in information about the elementary deformation mechanisms dominating the plastic behaviour of the material. Besides, there is interest in the influence of temperature on deformation localization through the development of micro and macro shear bands in the layers and across the layer boundaries. The extent and effects of deformation localization will be analyzed by electron microscopy.