【摘要】 利用纳米压痕实验以及四探针法,系统研究了相同层厚Cu/X(X=Cr,Nb)纳米金属多层膜的力学性能(强/硬度)和电学性能(电阻率)的尺度依赖性.微观分析表明:Cu/X多层膜调制结构清晰,Cu层沿{111}面择优生长,X层沿{110}面择优生长.纳米压入结果表明,Cu/X多层膜的强度依赖于调制周期,并随调制周期的减小而增加.多层膜变形机制在临界调制周期(λ~c≈25 nm)由Cu层内单根位错滑移转变为位错切割界面.多层膜的电阻率不仅与表面/界面以及晶界散射相关,而且在小尺度下受界面条件显著影响.通过修正的FS-MS模型可以量化界面效应对多层膜电阻率的影响.Cu/X纳米多层膜可以通过调控微观结构实现强度-电导率的合理匹配.更多还原

【Abstract】 By using nanoindentation test and four point probe method,the length scaled dependent mechanical property(hardness/strength) and electrical property(resistivity) of Cu/X(X=Cr, Nb) nanostructured metallic multilayers with equal individual layer thickness were systematically investigated. It is revealed from the microstructural analysis that the modulation structure of Cu/X metallic multilayers is clear,and the preferred growth planes of Cu layer and X layer are {111} and {110},respectively.The indentation test shows that the hardness/strength of the multilayers increases with reducing modulation periodλ.The deformation mechanism of the multilayers transits from the glide of single dislocation in a Cu layer to the interface cutting at a critical modulation periodλ~c (λ~c≈25 nm).The resistivity of Cu/X multilayers is not only related to the scattering of conduction electrons at surfaces/interfaces and grain boundaries,but also affected by the interface condition at small scale.This significant interface effect on the length scale-dependent resistivity is assessed using a modified FS-MS model.The best combination of strength-resistivity can be achieved by tailoring the microstructure of Cu/X nanostructured metallic multilayers.更多还原