Powder metallurgy technology encompasses a wide spectrum and has undergone countless changes in the last few years, both from a material or processing standpoint. Significant advances in powder manufacturing techniques have given rise to new types of powders with superior properties. These materials include multi-component composites, non-equilibrium materials like amorphous and microcrystalline, or metastable alloys including nano-crystalline materials. The size of the end PM product has increased many times and large parts including billets are commonly produced in large quantities. The method of powder production influences particle chemistry and structure, apart from the precise nature of particle size distribution. These properties also influence the behaviour of the powder during compaction and sintering, and the composition, structure and properties of the sintered material. Sintering is a complex process and for any given metal and set of sintering conditions there are likely to be different stages, driving forces and material transport mechanisms associated with the process. Furthermore, materials with properties far exceeding those of more conventional materials have been developed using new alloying elements and improved heat treatments. Upcoming researchers must be aware of different variables and their possible interrelations in achieving the final PM product. He/she must know what the end product is aiming at e.g. high strength, high density/porosity, high functional requirements etc.
Keeping the above expanded view of PM in mind, the role of researchers reaches far wider than it previously has, in turn putting higher demands on research staff. The present article highlights some of the issues, which a fresh researcher has to bear in mind.
This article appeared in the July–August 2019 issue of Metal Powder Report.
