Title: Dislocation dynamic simulation of dislocation pattern evolution in the early fatigue stages of aluminium single crystal

Authors: Jinxuan Bai; Qingshun Bai; Xin He; Qingchun Zhang

Addresses: School of Mechanical and Electrical Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, Harbin 150001, China ' School of Mechanical and Electrical Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, Harbin 150001, China ' School of Mechanical and Electrical Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, Harbin 150001, China ' School of Mechanical and Electrical Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Nan Gang District, Harbin 150001, China

Abstract: The two-dimensional discrete dislocation dynamics simulations under fully periodic boundary conditions has been employed to study the dislocation pattern evolution in the early stages of fatigue in aluminium single crystal. Long-range force among of dislocations is solved by line elasticity model, and short-range force is obtained by constitutive equations of dislocation nucleation, slip, pileup and annihilate. Dislocation movement mechanisms of single-slip-oriented and multi-slip systems are simulated and the evolution process of fatigue pattern is revealed. The result shows that dislocation quantity and microstructure strongly depend on external load and internal configuration. The dislocation pattern of single-slip-oriented generate matrix wall, and positive dislocations are vertical alignment and negative dislocations are at the angle of 45° with slip oriented in the initial stage. For multi-slip system, maze structure of dislocations is produced during dislocation multiplication, which eventually transforms into persistent slip band. The result is consistent with the existing experiment.

Keywords: aluminium single crystals; single crystal aluminium; early fatigue stages; dislocation patterns; discrete dislocation dynamics; simulation; microstructure; slip band.

DOI: 10.1504/IJNM.2017.082407

International Journal of Nanomanufacturing, 2017 Vol.13 No.1, pp.12 - 22

Received: 10 Aug 2015
Accepted: 04 Jan 2016
Published online: 23 Feb 2017 *

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