3D finite element temperature field modelling for direct laser fabrication

In order to describe the thermal dynamics behaviour in direct laser fabrication (DLF), a 3D finite element temperature field model is proposed to be built/developed based on global model and sub-model pattern. The global model exhibits the heat conduction characteristics of parts in the whole thermal history according to scanning path planning. Contact pairs and gap elements, which consider the effect of the temperature and porosity-dependent thermal conduction, are designed in the model to explain powder-to-solid intrinsic transition. In addition, the elements removed and reactivated technology is applied in the model so as to embody the material stepwise increasing feature. A laser-repairing case developed by ABAQUS demonstrates the global model's thermal history, and the influence of non-linear behaviour of thermal properties in pure nickel on the temperature distribution is estimated as well. Adopting the thermal physical parameters with solid-liquid phase change will make the melted pool temperature higher than that where the solid-liquid phase change parameters are not considered.