Layer Thickness-Dependent Hardness and Strain Rate Sensitivity of Cu–Al/Al Nanostructured Multilayers
来源期刊：Acta Metallurgica Sinica2016年第2期
论文作者：Ya-Qiang Wang Zhao-Qi Hou Jin-Yu Zhang Xiao-Qing Liang Gang Liu Guo-Jun Zhang Jun Sun
文章页码：156 - 162
摘 要：Cu–Al/Al nanostructured metallic multilayers with Al layer thickness hAlvarying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The results showed that the hardness increased drastically with decreasing hAldown to about 20 nm, whereafter the hardness reached a plateau that approaches the hardness of the alloyed Cu–Al monolithic thin films. The strain rate sensitivity（SRS, m）,however, decreased monotonically with reducing hAl. The layer thickness-dependent strengthening mechanisms were discussed, and it was revealed that the alloyed Cu–Al nanolayers dominated at hAlB 20 nm, while the crystalline Al nanolayers dominated at hAl[ 20 nm. The plastic deformation was mainly related to the ductile Al nanolayers, which was responsible for the monotonic evolution of SRS with hAl. In addition, the hAl-dependent hardness and SRS were quantitatively modeled in light of the strengthening mechanisms at different length scales.
Ya-Qiang Wang1，Zhao-Qi Hou1，Jin-Yu Zhang1，Xiao-Qing Liang1，Gang Liu1，Guo-Jun Zhang2，Jun Sun1
1. State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University2. School of Materials Science and Engineering, Xi’an University of Technology
摘 要：Cu–Al/Al nanostructured metallic multilayers with Al layer thickness hAlvarying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The results showed that the hardness increased drastically with decreasing hAldown to about 20 nm, whereafter the hardness reached a plateau that approaches the hardness of the alloyed Cu–Al monolithic thin films. The strain rate sensitivity（SRS, m）,however, decreased monotonically with reducing hAl. The layer thickness-dependent strengthening mechanisms were discussed, and it was revealed that the alloyed Cu–Al nanolayers dominated at hAlB 20 nm, while the crystalline Al nanolayers dominated at hAl[ 20 nm. The plastic deformation was mainly related to the ductile Al nanolayers, which was responsible for the monotonic evolution of SRS with hAl. In addition, the hAl-dependent hardness and SRS were quantitatively modeled in light of the strengthening mechanisms at different length scales.
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