Temporal development of melt-pool morphology and clad geometry in laser powder deposition

A transient finite element approach is developed to simulate the temporal evolution of the melt-pool morphology and dimensions during laser powder deposition. The in-process addition of material is numerically carried out in a coupled manner through activation of a new set of elements within each solution time step. The geometry of the deposited material is finely predicted without assuming any of the geometrical characteristics, such as height, width, and/or the general shape, as a priori. Experimental verification of the model for deposition of AISI 304L reveals a good agreement between the predicted and measured temperature and geometry of the deposited material. The model presents a high accuracy in simulation of 3D melt-pool morphology and geometry in deposition of Ti45Nb on Ti–6Al–4V. It is shown, using the developed model, that local solidification conditions, i.e., the temperature gradient and interface velocity, can be accurately evaluated along the predicted solid/liquid interface. Moreover, the presented model is able to show the effect of the laser scan velocity on the amount of dilution from the substrate.

Research highlights
► The clad and melt-pool geometry is predicted without assuming any pre-defined shape.
► The melt-pool is simulated with a realistically inclined surface morphology.
► The 3D solid/liquid interface morphology is modelled with a satisfactory resolution.
► Local conditions of constraint solidification can be found along the 3D interface.