调制波长对Cu／Ni金属多层膜力学性能的影响

Effect of Modulation Wavelength in Cu/Ni Multilayers on Mechanical Properties

摘要:

用电沉积法在低碳钢基体上制备了具有不同调制波长(一个调制波长等于单层Cu膜与单层Ni膜厚度之和)的Cu/Ni金属多层膜，研究了多层膜硬度与其中单层膜厚度之间的关系。结果表明，当膜厚在亚微米范围内时，Cu/Ni多层膜的屈服强度(为硬度值的1/3)与单层膜厚之间符合基于位错塞积模型的Hall-Pctch(H-P)关系式；而当单层膜厚小于100nm时，屈服强度与膜厚的关系偏离了H-P线性关系。基于程开甲等人位错稳定性理论首次对金属多层膜变形行为偏离Hall-Petch关系的现象作了定量解释。

Abstract:

Cu/Ni multilayers with various modulation wavelengths were deposited on a low carbon steel substrates by electrode positing method. Hardness measurements identified that the relationship between the yield strength (one-third of hardness) which increased with decrease of layer thickness for Cu/Ni multilayers and single layer thickness at sub-micron length scale--- could be described by the Hall-Petch (H-P) formula for dislocation pile-up. In the regime of few tens to a hundred nanometer of single layer thickness, the dislocation pileup-based H-P model breaks down. This can be explained in terms of the limiting dislocation size criterion proposed by Cheng et al.