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| Effects of collision cascades on the mechanical properties of pearlites |
| 1,Minsheng Huang1,Li Zhenhuan |
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Abstract Lamellar pearlites consisting of ferritic and cementite layer is a kind of common metallographic structure in ferritic-alloyed steels, the most widely used structural materials in nuclear energy engineering. Understanding the irradiation effects on the mechanical behaviors of lamellar pearlites is of importance for designing and life-prediction of such materials under high-irradiation conditions. By implementing molecular dynamics simulations, the microstructure variation of cementite/ferritic interface in lamellar pearlites caused by successive low-energy collision cascades are investigated. Besides, the initial yielding behaviors for lamellar pearlites experienced different dose of irradiation are discussed for both uniaxial tensile and compressive loadings. The main conclusions can be summarized as follows: A) The irradiation can destroy the structure of misfit dislocation arrays on the interface, and further promote the diffusion of carbon atoms from the interface to the ferritic phase. B) Under uniaxial tensile loading, collision cascades change the yielding initiation from the activation of {112}<111> slip system to the nucleation and expansion of dislocation loop from the interstitial clusters. C) Under uniaxial compressive loading, collision cascades change the yielding initiation from the activation of {110}<111> slip system to the activation of {112}<111> slip system. D) For both tensile and compressive loading types, the dislocation nucleation stress (or yielding stress) can be increased by the irradiation effects. These results may provide new nano-scale explanations on the irradiation hardening and embrittlement and shed light on the optimal design for ferritic-alloyed steels working under the irradiation environments
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Received: 31 December 2019
Published: 28 December 2020
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Corresponding Authors:
Minsheng Huang
E-mail: mshuang@hust.edu.cn
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2020, Vol. 41 
