纳米多层膜“软"相结构参量对硬度的Hall-Petch表征

采用直流磁控溅射方法制备了不同调制比的Ni/Al纳米多层膜，利用X射线衍射技术和纳米压入连续刚度法分析了薄膜微结构及塑性变形的尺度依赖性.实验结果表明，尽管调制比有所不同，多层膜的硬度与“软"相的微结构特征参量随调制波长减小具有相似变化规律，说明多层膜的变形机制对“软"相的微结构约束存在敏感性.随着薄膜特征尺度的减小，为统一多层膜中晶界和膜界两种强化机制，提出一个与“软”相相关的表征参量r(r＝L_sub/d，L关键词：纳米多层膜塑性变形调制波长Hall-Petch关系

Characterization of Hall-Petch relation on microstructural parameter of softer sublayer and the hardness in nanomultilayers

Scale dependent microstructures and plastic deformation in Ni/Al nanomultilayers with different modulated ratio has been investigated as a function of bilayer thickness by X-ray diffraction and nanoindentation. Experimental results show that the hardness and the related microstructural parameter in the softer sublayer exhibited the similar variation tendency, which indicated the sensitivity of plastic behaviors on the microstructural constraints in softer sublayer. Further investigation showed that in the nanometer regime, by adopting a new parameter r in softer sublayer (r=L_sub/d, where L_sub is the sublayer thickness and d is the grain size), the competing grain-boundary and interface-boundary strengthening mechanisms could be unified. Moreover, within the overall scale, the deformation of nanomultilayers could follow the Hall-Petch relation with decreasing characteristic length scales.