New scientific approaches to development of tool materials

AbstractThe most active areas of research and development in tool materials are those dealing with new materials and processes, especially in ‘coatings’ and ‘ceramics'. Effective coating compounds such as TiC, TiN, and Al2O3 have high hardness and good chemical stability. Fundamental research attempts to link wear resistance to the nature of interatomic bonding in refractory compounds. Ceramic tool materials also offer high hardness and chemical stability, but lack fracture toughness and thermal shock resistance. Current development proceeds in the direction of composites and transformation toughening. An impressive degree of understanding of the chemistry, constitution, and sintering reactions has been achieved in a very short time on Al2O3- and Si3N4-base ceramics. The physical metallurgy of cemented carbides continues to be of interest for purposes of control and quality improvement. The availability of high resolution electron microscopy has revealed previously unsuspected complexity in the microstruc...