Metal Injection Moulding of Iron-Base Oxide Dispersion Strengthened Alloys

摘要

Iron-base oxide dispersion strengthened (ODS) alloys offer high elevated temperature strength, good creep resistance as well as good oxidation resistance. Conventional production routes for ODS materials include consolidation of mechanically alloyed powders by hot isostatic pressing or extrusion followed by forging, rolling and machining which is very costly. Metal injection moulding (MIM) is a cost-effective production technology that allows the fabrication of near-net shape parts. This study concerns the feasibility of manufacturing parts via MIM from an iron-base ODS alloy based on PM2000. The optimum thermal process parameters will be determined. ODS alloys pose a serious challenge for MIM processing, because the powder has a non-spherical morphology after mechanical alloying. Differential scanning calorimetry (DSC) and dilatometry measurements as well as ThermoCalc simulations are used to optimize the sintering step of the MIM process route. Carbon, nitrogen and oxygen contents of the powder and the as sintered specimens are measured to evaluate the pick up of impurities during processing. The microstructure of the as sintered specimens is characterized with respect to density, residual porosity and formation of phases. Ways to successfully process MIM ODS parts will be discussed.