Post Treatment Process and Selective Laser Sintering Mechanism of Polymer-Coated Mo Powder

ABSTRACT

A novel preparing method of polymer-coated molybdenum powder was presented. A type of multi-component polymer-coated molybdenum powder was chosen for selective laser sintering. The effect of the process parameters on the part's characteristics is investigated. Based on our study for dynamic laser sintering process of polymer-coated molybdenum powder, its laser sintering mechanism was reported as follows: at the early stage of laser sintering, the viscous flow is the major mechanism; during the laser sintering, the melting/solidification is the major mechanism. Furthermore, a model corresponding to the mechanism was discussed schematically, which could be used to explain the material migrating mode during laser sintering process. The laser sintering experiments of polymer-coated Mo powder was conducted in the self-developed laser sintering machine, and optimized parameters have been acquired. At last, the post treatment process of laser sintered parts has been developed and refractory metal parts of Mo/Cu composites are gained. The post treatment process includes debinding, high temperature sintering and melting infiltration, which is sintering framework-Mo by high temperature combining with Cu impregnation method. It is found that the mechanical properties of parts have been greatly improved after the post treatment process.