A critical evaluation of indentation techniques for measuring the hardness vs toughness: A review

To obtain a reasonable relationship between fracture toughness and hardness of a certain material has become a great importance these days. The material for production of any machine parts or for any commodities needs to be tough enough in order to withstand the stress causing deformation, as well as it should be hard enough for resisting any type of surface penetration or abrasion. The fracture toughness was measured by palmqvist method and the hardness was measured by Vickers indentation technique. In general, the higher the hardness of the alloys, the longer was the indentation cracks, indicating a decrease in fracture toughness with increasing hardness. However, at certain hardness, the toughness of individual alloys varied significantly. The fracture toughness and hardness of both WC-Co hard metal vary in opposite ways, if the composition or the microstructure of the materials are varied, but this type of relationship by the entire publisher does not at all agree this theory.