Powder metallurgy opens new ways for tool steels

Powder metallurgy permits to produce tool steels with finer microstructure and improved mechanical properties compared to wrought ones. This major advantage was recently used by the authors in designing new steel grades combining higher strength and toughness. Novel hybrid tool steels, by mixing hot work and high speed steel powders in different proportions, were developed looking at materials with properties tunable for a specific application. Near ultrafine grained materials could be obtained combining mechanical milling and spark plasma sintering, a fast consolidation technique assisted by pulsed current. Particle reinforced tool steel matrix composites have also been produced using the same approach. Finally, in order to look for steels combining high hardness and improved thermal conductivity hybrid tool steel-Cu grades were sintered. The aim of the present paper is to give a general overview of the research activities and the opportunities opened by these new powder metallurgy products.