Properties of WC-10%(Ni-Fe) Alloys

Some properties of WC-10% (Ni-Fe) alloys sintered in vacuum at 1450°C for lhr were examined in relation to their carbon contents. Main results obtained are as follows ;(1) The two-phase region was observed only in the alloys of which binder compositions were up to about 50% Fe in binder. Therefore, the properties of these alloys showed a regular change with the change of the carbon content in the alloys. (2) However, as the amount of Fe increased in those alloys, the contraction of the two-phase region, the shift of the region towards the higher carbon side and the decrease of the amount of dissolved W in binder phase of low carbon alloys were observed. (3) Following facts were also observed in the alloys having binder compositions of more than about 75% Fe in binder. i) mingling of b. c. c. binder phase with f. c. c. one, ii) fixed compositions of binder phase, regardless of the wide variation in the carbon content, iii) disappearance of the two phase region, iv) formation of M23C6 type compound. (4) Hardness of the alloys increased with increasing Fe content and reached a maximum at the binder composition of about 90% Fe in binder. Transverserupture strength decreased with a small amount of addition Fe and did not change mostly in the range of binder compositions from 10 to 75% Fe. Thus, it was shown that the alloy having binder composition of 75% Fe exhibited the most excellent mechanical properties. However, the strength was much inferior to that of WC-Co alloys. (5) Grain growth of WC was highly inhibited by increasing of Fe content.