mo 2 c the materials where sintered at 1410 u00b0 c by sinter hip at 50 bar then the samples were polished and then hv30 and k1c properties measured the recipes used and measurements of hardness and toughness are shown in table 5 it can be seen that in all cases the additions of the mo both at the 0 05 and 0 15 mo co ratio has resulted in hardness with a slight reduction in toughness compared to the baseline as a similar response in material properties has been observed as for the 10 binder examples similar changes in performance can be expected from these materials it is also known that co can dissolve mo during sintering but after cooling retained mo might lead to reduced binder ductility and lower fracture toughness therefore inclusion of mo and probably cr also in carbide grade compositions should be regarded essentially as adding to the hard phase rather than providing an extra constituent to the ductile binder co is the key provider of ductility to hard metals grade toughness being determined by co volume fraction in relation to all other ingredients it should be appreciated that a variety of combinations of co and mo within the disclosed ranges as well as other ranges is contemplated and that the application should not be limited to just those combinations disclosed the effect upon grade toughness of partially replacing co with mo up to u02dc 2 vol in co u2014 cr 3 c 2 sub micron wc hard metal has been studied results of these studies show that hardness increased moderately and k1c decreased slightly with increasing replacement of co by mo average edge toughness as represented by number of.