Shear-induced softening of nanocrystalline metal interfaces at cryogenic temperatures

We demonstrate inverse Hall-Petch behavior (softening) in pure copper sliding contacts at cryogenic temperatures. By kinetically limiting grain growth, it is possible to generate a quasi-stable ultra-nanocrystalline surface layer with reduced strength. In situ electrical contact resistance measureme...

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Bibliographic Details
Published inScripta materialia Vol. 143; no. C
Main Authors Chandross, Michael, Curry, John F., Babuska, Tomas F., Lu, Ping, Furnish, Timothy A., Kustas, Andrew B., Nation, Brendan L., Staats, Wayne L., Argibay, Nicolas
Format Journal Article
LanguageEnglish
Published United States Elsevier 01.01.2018
Subjects
MATERIALS SCIENCE
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Summary:We demonstrate inverse Hall-Petch behavior (softening) in pure copper sliding contacts at cryogenic temperatures. By kinetically limiting grain growth, it is possible to generate a quasi-stable ultra-nanocrystalline surface layer with reduced strength. In situ electrical contact resistance measurements were used to determine grain size evolution at the interface, in agreement with reports of softening in highly nanotwinned copper. We also show evidence of a direct correlation between surface grain size and friction coefficient, validating a model linking friction in pure metals and the transition from dislocation mediated plasticity to grain boundary sliding.
Bibliography:SAND2017-11200J
NA0003525; AC04-94AL85000
USDOE National Nuclear Security Administration (NNSA)
ISSN:1359-6462
1872-8456