Linking microstructural evolution and macro-scale friction behavior in metals

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• 作者：N. Argibay ; M. Chandross ; S. Cheng ; J. R. Michael
• 刊名：Journal of Materials Science
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：52
• 期：5
• 页码：2780-2799
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Materials Science, general; Characterization and Evaluation of Materials; Polymer Sciences; Continuum Mechanics and Mechanics of Materials; Crystallography and Scattering Methods; Classical Mechanics;
• 出版者：Springer US
• ISSN：1573-4803
• 卷排序：52

文摘

A correlation is established between the macro-scale friction regimes of metals and a transition between two dominant atomistic mechanisms of deformation. Metals tend to exhibit bi-stable friction behavior—low and converging or high and diverging. These general trends in behavior are shown to be largely explained using a simplified model based on grain size evolution, as a function of contact stress and temperature, and are demonstrated for self-mated pure copper and gold sliding contacts. Specifically, the low-friction regime (where µ < 0.5) is linked to the formation of ultra-nanocrystalline surface films (10–20 nm), driving toward shear accommodation by grain boundary sliding. Above a critical combination of stress and temperature—demonstrated to be a material property—shear accommodation transitions to dislocation dominated plasticity and high friction, with µ > 0.5. We utilize a combination of experimental and computational methods to develop and validate the proposed structure–property relationship. This quantitative framework provides a shift from phenomenological to mechanistic and predictive fundamental understanding of friction for crystalline materials, including engineering alloys.