Atomic-scale simulations of ideal strength and deformation mechanism in β-SiC under H/He irradiation. Issue 5 (1st April 2019)

• Record Type: Journal Article
• Authors: Lu, Xiaoke; Chen, Xuanyu; Feng, Yajuan; Shi, Panhua; Wei, Tianhao; Liu, Wing-Chung; Wang, Yuexia
• Is Part Of: Ceramics international. Volume 45:Issue 5(2019)
• Page Start: 6125
• Page End: 6134
• Publication Date: 2019-04-01
• Subjects: β-SiC ceramic -- Ideal strength -- Deformation mechanism -- H/He irradiation; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.12.087
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: We firstly investigated the mechanical responses of β-SiC to the tensile and shear strains under H/He irradiation using density functional theory, with a specific focus on the atomistic mechanism of deformation and fracture. The results revealed that the effect of introducing H/He on ideal strengths of tension and shear is limited, due to the strong sp 3 bonds of Si-C. However, somehow large disparity in failure was discovered after introducing H/He. Under the tension, all Si-C bonds along the tensile direction are synchronously broken, causing cubic-to-graphitic transformation in the perfect β-SiC, in contrast to the asynchronous breakage of Si-C bonds in the H/He-doping systems. Under the shear, H- and He-doping systems display individual cleavage-like modes of lattice instability, respectively, whereas structural transformation by re-bonding new Si-C bonds is responsible for the failure in the perfect β-SiC. The cleavage-like modes were discussed, combining a detailed analysis of electronic structure. The mechanical response to H/He irradiation distinguishes β-SiC from conventional metals presently applied in nuclear industry. The study may provide a clue for new design strategy of irradiation-tolerant materials for energy applications.