Increasing nanoparticle volume fraction has been proved to be effective in improving the strength of nanoparticle reinforced Al matrix nanocomposite.However,the underlying mechanisms for the ultrahigh strength of those nanocomposites with high volume fraction(＞10 vol.％)nanoparticles are short of experimental research.In this study,the strengthening mechanisms of high strength Al matrix nanocomposite reinforced with 15 vol.％Al2O3 nanoparticles were investigated experimentally and analyzed theoretically.The results show that the thermal mismatch induced geometrically necessary dislocations exhibit a negligible strengthening effect,because of their low density in the nanocomposite that is contradiction to the conventional dislocation punch model.Orowan mechanism makes a major strengthening contribution in view of the deformation process dominated by nanoparticle-dislocation interactions due to the extreme pinning effect of nanoparticles on dislocation motion.In addition,the several mechanisms including grain boundary strengthening,load transfer strengthening,and elastic modulus mismatch induced dislocation strengthening contribute to the strength increase.

Ke Zhao;Zhongying Duan;Jinling Liu;Guozheng Kang;Linan An

School of Mechanics and Engineering,Southwest Jiaotong University,Chengdu 610031,China;Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,Southwest Jiaotong University,Chengdu 610031,China;Department of Materials Science and Engineering,University of Central Florida,Orlando,FL 32816,USA

金属学报（英文版）

[1]Ke Zhao;Zhongying Duan;Jinling Liu;Guozheng Kang;Linan An-.Strengthening Mechanisms of 15 vol.％Al2O3 Nanoparticles Reinforced Aluminum Matrix Nanocomposite Fabricated by High Energy Ball Milling and Vacuum Hot Pressing)[J].金属学报（英文版）,2022(06):915-921

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