Microstructure and Mechanical Characteristics of DMLS Tool-Inserts

A commercial metal powder mixture was used for the laser sintering experiments. Different substrates in the form of simple blocks and complex testing tool-inserts for pressure die casting of Al-based alloy were prepared at different process conditions and post-surface treatments. Additional improvement of surface quality was obtained with the hard coating. In the present article, the basic principles of laser sintering are presented. Morphological and microstructure properties of metal powders and sintered products are also discussed. The results show that relatively porous and heterogeneous microstructures are obtained during laser sintering in the presence of the liquid phase. However, improved properties of the laser-sintered products can be obtained by careful selection and control of powder properties, optimization of direct metal laser sintering conditions, and by the hard coating of the sintered product.