Gradient elasticity for disclinated micro crystals. (October 2018)

• Record Type: Journal Article
• Authors: Tsagrakis, Ioannis; Yasnikov, Igor S.; Aifantis, Elias C.
• Is Part Of: Mechanics research communications. Volume 93(2018)
• Page Start: 159
• Page End: 162
• Publication Date: 2018-10
• Subjects: Gradient elasticity -- Disclinations -- Pentagonal symmetry -- Decahedral particles -- Icosahedral microcrystals -- Electrodeposition; Mechanics, Applied -- Periodicals; Mécanique appliquée -- Périodiques; Mechanics, Applied; Periodicals; 530
• DOI: 10.1016/j.mechrescom.2017.11.007
• Languages: English
• ISSNs: 0093-6413

Abstract

Highlights: A model of gradient elasticity is used to obtain nonsingular stress fields in disclinated microcrystals (DMCs) of pentagonal symmetry. Both solid and hollow icosahedral small particles (ISPs) are considered and a general expression for the strain energy is derived for the latter. Vacancies formed on the surface of a growing crystal move toward its center with a nonsingular drift velocity generated by the hydrostatic stress field. Drift velocity of vacancies increases as the crystal size grows promoting void formation via vacancy agglomeration. A stress-assisted diffusion model is also employed to describe the concentration of vacancies at the initial stages of the void formation. Abstract: This article, dedicated to the memory of Gérard Maugin, can be considered as an outgrowth of a series of papers on gradient elasticity jointly published by him, the third author and their collaborators. It focuses on the use of nonsingular solutions for describing stress relaxation in disclinated microcrystals (DMCs) of pentagonal symmetry, fabricated by electrodeposition. This is an important area of current experimental and theoretical activity since such internally stressed DMCs are also characterized by extended surface (large surface to volume ratio) and have been shown to accelerate chemical reactions and purification processes. Previous theoretical models based on classical elasticity exhibit certain undesirable features due to singularities. Some of them are revisited here by eliminating disclination singularities through gradient elasticity.