抄録
Two series of WC-5%TaC-10%Co alloys, using two different methods of adding of the tantalum carbide, i.e., additions in the forms of the straight TaC and of (Ta, W)C mixed carbide, were vacuum-sintered at 1375°C for 1.5hr. Studies on the effects of the adding methods and the grain size of the tantalum carbide on some properties of the alloys were carried out. Carbon contents of the alloys were minutely controlled.
The main results obtained were as follows : (1) The adding methods and the grain size of the tantalum carbide in the specimens did not affect the properties of the alloys such as the composition of the binder phase, the width and the position of three phase range, the hardness and density. Moreover, they appeared to have no relation to the inhibition-effect of tantalum carbide on the recrystallization of the WC phase. (2) The transverse-rupture strength of the alloys, however, was affected by the grain size of tantalum carbide and was greatly improved by the grain refinement. (3) In the case of addition in the from of (Ta, W)C mixed carbide, the strength of the alloys appeared to be superior to the other case, under an approximately same grain size of tantalum carbide. The reason for this superiority of the strength was not clear.
