抄録
Effects of carbon content on the properties of WC-10%Fe, WC-5%Fe-5%Co and WC2.5%Fe-7.5%Co alloys (sintered in vacuum at 1450°C for 1 hr) were studied. The results are summarized as follows;
(1) Sintering temperature of these alloys was higher than that of WC-Co alloys.
(2) In WC-Fe alloys and also in WC-Fe-Co alloys containing less than 50-60%Co as binder, tungsten dissolved scarcely into binder phase irrespective of the carbon content in the alloys. This is an essential difference between WC-Fe base alloys and WC-Co ones.
(3) Magnetic saturation of WC-Fe alloy was not constant in the phase region in which free carbon formed, due to the formation of the complex carbide phase. Similar result was observed also in WC-Fe-Co alloys containing less than 50-60%Co in binder. Magnetic saturation of WC-Fe alloy with extremely high carbon content was equal to the value estimated by assuming that the binder consists of pure iron. Magnetic saturation of each alloy with extremely low carbon content decreased due to the formation of M 6C type compound (η phase).
(4) WC-Fe and WC-Fe-Co alloys contained M23C 6 or (M23C 6+M3C) type compounds in the region corresponding to the two phase region in WC-Co alloys. It appears that the region in WC-Fe-Co alloys shifts to the lower carbon side compared with that of WC-Co alloy.
(5) Transverse-rupture strength of WC-Fe alloy showed a maximum value at the carbon content at which a large amount of free carbon was formed. The carbon content giving maximum strength decreased with increasing cobalt content.
(6) Strength of WC-Fe and WC-Fe-Co alloys was inferior to that of WC-Co base and WC-Ni alloys. This might be due to the formation of complex carbide even in the region correspon-ding to the two phase region of WC-Co base alloys and also due to the fact that the binder was b.c.c. alloy more brittle than f.c.c. In WC-Fe-Co alloys solution-hardning might be respon-sible also.
