Finite element analysis of the effect of volume shrinkage during laser densification

Effects of the volume shrinkage due to transformation from a powder compact to dense liquid on the temperature distribution and the size of the transformation zone during laser densification have been investigated using a three-dimensional finite element model. The dependence of the volume shrinkage effect on the mesh size of the model and the criterion used to judge whether an element remains as powder or becomes liquid has also been evaluated. The results of the simulation have been compared with the experiment, and it is found that the simulation matches the experiment very well. Furthermore, this study also indicates that simplified models that do not include the local geometry change due to the volume shrinkage during densification provide good estimations of the temperature field and the size of the laser-densified body, although the shape of the laser-densified body predicted is different from that obtained in the experiment.