Dislocation structures formation induced by thermal stress in additive manufacturing: Multiscale crystal plasticity modeling of dislocation transport

• DOI: 10.1016/j.jmps.2023.105235
• Publication Date: 2023-02-09T05:22:08Z
• Authors: Daijun Hu; Nicolò Grilli; Wentao Yan
• Keywords: Peierls stress

The motion of dislocations governs the plastic deformation crystalline materials, which in turn determines mechanical properties. complex thermal history, large temperature gradients and high cooling rates during process additive manufacturing (AM) can induce dislocation density unique structures material. origin these their stability loading are debated. A novel dependent continuum dynamics (CDD) model is developed, four state variables used for each slip system representing total density, edge screw geometrically necessary densities curvature. CDD fully coupled with a crystal plasticity solver, captures induced by motion. hybrid continuous discontinuous Galerkin formulation developed to accurately reproduce highly fields that typical structures. multiscale modeling approach used, thermally specific grains polycrystal extracted from larger scale simulations laser powder-bed fusion process, then single simulations. Simulation results reveal structure formation at different positions scanning stages. effect cyclic stress multi-layer AM fabrication also investigated. provide new perspective on conditions should be satisfied stable