This work was supported by the Shenzhen Fund 2021 Basic Research General Programme (project code: JCYJ20210324115400002) and Hong Kong Research Grants Council Collaborative Research Fund C1005–19 G. The work of Y.X. was also supported by the Project of Hetao Shenzhen-HKUST Innovation Cooperation Zone HZQB-KCZYB-2020083.
The first movie shows the DDFD simulation of Frank-Read source as one of the main mechanisms for the dislocation line generation during plasticity. The second movie shows the simulation of Orowan looping as one of the hardening mechanism existing in metals and alloys. It shows how a gliding dislocation line interacts with an obstacle and how the loops form around every obstacle. The third and fourth movies show how a bundle of dislocation lines evolve while using a governing equation for “all-dislocation” density kinematics: in the former, a free boundary condition is assigned that the dislocation lines reach the boundary and move out from the simulation cell without any obstacle, while in the latter, an impenetrable boundary condition is applied that the dislocation lines reach the boundary and pile up in front of the boundary.
This paper has further details:
An efficient and minimalist scheme for continuum dislocation dynamics, Alireza Kalaei, Yang Xiang, and Alfonso H.W. Ngan, Int. J. Plast. 158, 103433 (2022). (doi:10.1016/j.ijplas.2022.103433) (abstract)This work is supported by funding from Kingboard Endowed Professorship in Materials Engineering, as well as a Seed Grant for Basic Research from The University of Hong Kong (Project code: 201411159129).
The first movie shows how two straight dislocation lines move in opposite directions and annihilate each other. The second and third movies show dislocation loop expansion and contraction under a fixed stress. The fourth and fifth movies show simulation of Orowan looping in applied stress. In the former, the applied stress is not adequate to complete the Orowan looping mechanism while increasing the applied stress resulted in completing the Orowan looping in the latter.
This paper has further details:
Dislocation-density function dynamics – An all-dislocation, full-dynamics approach for modeling intensive dislocation structures, H.S. Leung and A.H.W. Ngan, J. Mech. Phys. Solids 91, 172–203 (2016). (doi:10.1016/j.jmps.2016.03.008) (abstract)