title: Mechanical properties for irradiated face-centred cubic nanocrystalline metals.
abstract: In this paper, a self-consistent plasticity theory is proposed to model the mechanical behaviours of irradiated face-centred cubic nanocrystalline metals. At the grain level, a tensorial crystal model with both irradiation and grain size effects is applied for the grain interior (GI), whereas both grain boundary (GB) sliding with irradiation effect and GB diffusion are considered in modelling the behaviours of GBs. The elastic-viscoplastic self-consistent method with considering grain size distribution is developed to transit the microscopic behaviour of individual grains to the macroscopic properties of nanocrystals (NCs). The proposed theory is applied to model the mechanical properties of irradiated NC copper, and the feasibility and efficiency have been validated by comparing with experimental data. Numerical results show that: (i) irradiation-induced defects can lead to irradiation hardening in the GIs, but the hardening effect decreases with the grain size due to the increasing absorption of defects by GBs. Meanwhile, the absorbed defects would make the GBs softer than the unirradiated case. (ii) There exists a critical grain size for irradiated NC metals, which separates the grain size into the irradiation hardening dominant region (above the critical size) and irradiation softening dominant region (below the critical size). (iii) The distribution of grain size has a significant influence on the mechanical behaviours of both irradiated and unirradiated NCs. The proposed model can offer a valid theoretical foundation to study the irradiation effect on NC materials.
authors.affiliation: State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, People's Republic of China; CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China.
authors.forename: X Z
authors.initials: XZ
authors.lastname: Xiao
authors.affiliation: State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering , Peking University , Beijing 100871, People's Republic of China.
authors.forename: D K
authors.initials: DK
authors.lastname: Song
authors.affiliation: Department of Mechanics and Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200444, People's Republic of China; State Key Laboratory for Mechanical Behavior of Materials, Xi'an 710049, People's Republic of China.
authors.forename: H J
authors.initials: HJ
authors.lastname: Chu
authors.affiliation: CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China; State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, People's Republic of China.
authors.forename: J M
authors.initials: JM
authors.lastname: Xue
authors.affiliation: State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, People's Republic of China; CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China.
authors.forename: H L
authors.initials: HL
authors.lastname: Duan
keywords: Hall–Petch; grain boundary; irradiation effect; nanocrystalline materials; self-consistent method