Effects of Particle Size and Alloy Chemistry on Processing and Properties of MIM Powders

摘要

The continuing growth in the MIM market is testament to a number of factors including growing diversity in applications, the increasing ingenuity shown by designers, the flexibility and cost effectiveness of the technology and growing capacity in the MIM supply chain. In selecting a particular powder for a given application, MIM designers consider processing performance, finished properties and total unit cost of the component including starting powder and processing route. In this paper, we reflect on some of the differences in behaviour of gas and water atomised powders and on gas atomised powders with different particle size distributions. Data are presented to illustrate effects of particle size on processing aspects and properties of precipitation hardened stainless steel parts. It is proposed that the lower oxygen levels and spheroidal shape of gas atomised powders provide benefits which are apparent throughout processing and offer opportunities for lower processing costs, improved quality and higher value addition in finished products.