Initial dislocation density effect on strain hardening in FCC aluminium alloy under laser shock peening |
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Authors: | Wangfan Zhou Yunpeng Ren Shouqi Yuan Naifei Ren Xueqing Yang |
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Affiliation: | 1. School of Mechanical Engineering, Jiangsu University, Zhenjiang, PR China;2. Research Center of Fluid Machinery Engineering and Technical, Jiangsu University, Zhenjiang, PR China |
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Abstract: | AbstractThe effect of initial dislocation density on subsequent dislocation evolution and strain hardening in FCC aluminium alloy under laser shock peening (LSP) was investigated by using three-dimension discrete dislocation dynamics (DD) simulation. Initial dislocations were randomly generated and distributed on slip planes for three different dislocation densities of 4.21 × 1012, 8.12 × 1012 and 1.26 × 1013 m?2. Besides, variable densities of prismatic loops were introduced into the DD cells as nanoprecipitates to study the dislocation pinning effect. The flow stresses as a function of strain rate obtained by DD simulation are compared with relevant experimental data. The results show a significant dislocation density accumulation in the form of dislocation band-like structures under LSP. The overall yield strength in FCC aluminium alloy decreases with increasing initial dislocation density and forest dislocation strengthening becomes negligible under laser induced ultra-high strain rate deformation. In addition, yield strength is enhanced by increasing the nanoprecipitate density due to dislocation pinning effect. |
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Keywords: | Laser shock peening dislocation dynamics ultra-high strain rate material strength nanoscale precipitates surface treatments |
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