| Original Articles |
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Elastic Modulus and Hardness of Cr--Nb Nano-Multilayers |
| YANG Meng-Jin;LAI Wen-Sheng;PAN Feng |
| Laboratory of Advanced Materials, Department of Materials Science and Engineering,Tsinghua University, Beijing 100084 |
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| Cite this article: |
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YANG Meng-Jin, LAI Wen-Sheng, PAN Feng 2007 Chin. Phys. Lett. 24 2635-2638 |
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Abstract Cr--Nb nano-multilayered films with various modulation wavelengths Λ are prepared by e-gun evaporation and their mechanical properties are investigated. Cr and Nb both have bcc structures with large differences in lattice constants and Young's modulus, which are supposed to favour modulus enhancement. Nevertheless, nano-indention measurements show no enhancement for the modulus and a slight decrease for the hardness with decreasing Λ down to 6nm. This is mainly due to counter-contribution to modulus from adjacent layers subjected to reverse strains, in agreement with recent theoretical study, while the decrease of hardness arises from grain boundary sliding. Interestingly, at Λ= 3nm, the hardness of the film has an
increase of 44% relative to the value of a rule of mixture, owing to the emergence of a new phase for reconciling the structure difference at the interfaces.
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| Keywords:
62.25.+g
68.65.-k
68.65.Ac
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Received: 06 February 2007
Published: 16 August 2007
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| PACS: |
62.25.+g
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68.65.-k
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(Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties)
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68.65.Ac
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(Multilayers)
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