An improved method to model dislocation self-climb. (4th June 2020)

• Record Type: Journal Article
• Authors: Liu, Fengxian; Cocks, Alan C F; Gill, Simon P A; Tarleton, Edmund
• Is Part Of: Modelling and simulation in materials science and engineering. Volume 28:Number 5(2020)
• Publication Date: 2020-06-04
• Subjects: core diffusion -- pipe diffusion -- variational principle -- self-climb; Materials -- Mathematical models -- Periodicals; Matériaux -- Modèles mathématiques -- Périodiques; Materials -- Mathematical models; Periodicals; 620.00113
• DOI: 10.1088/1361-651X/ab81a8
• Languages: English
• ISSNs: 0965-0393

Abstract

Abstract: Dislocations can provide short circuit diffusion paths for atoms resulting in a dislocation climb motion referred to as self-climb. A variational principle is presented for the analysis of problems in which fast dislocation core diffusion is the dominant mechanism for material redistribution. The linear element based self-climb model, developed in our previous work [1] Liu, Cocks and Tarleton (2020 J. Mech. Phys. Solids 135 103783), is significantly accelerated here, by employing a new finite element discretisation method. The speed-up in computation enables us to use the self-climb model as an effective numerical technique to simulate emergent dislocation behaviour involving both self-climb and glide. The formation of prismatic loops from the break-up of different types of edge dislocation dipoles are investigated based on this new method. We demonstrate that edge dipoles sequentially pinch-off prismatic loops, rather than spontaneously breaking-up into a string of loops, to rapidly decrease the total dislocation energy.