少量のTaCを添加したWC-TaC-10%Co合金の性質について

Abstract

WC-TaC-10%Co alloys containing 0.5, 1.0, 3.0%TaC (added in the form of a mixed carbide) and having various carbon contents were vacuum-sintered at 1375°C for 2 hr. The particle size of the WC powder used was controlled to obtain an approximately same grain size of carbides in the sintered alloys. Some properties of the as-sintered alloys and the effect of low-temperature annealing (at 800°C up to 50 hr) on them were studied as a function of the TaC and carbon contents, using the experimental method as used in previous investigations(1)∼(4).The main results are as follows: (1) The relations(1)∼(4) recently obtained by the authors on sintered WC-Co straight alloys, namely, that the properties of two phase alloys are remarkably influenced by their carbon contents and also by low temperature annealing when the carbon contents are lower, are substantially maintained in the alloys containing TaC. (2) The composition of binder phase, width and position in the two phase range (a γ+TaC+WC three phase range) of the WC-TaC-10%Co alloys do not change by the addition of TaC. (3) The alloys containing TaC are higher in hardness than the straight alloys, but the strength scarcely decreases. (4) The aging rate at a low temperature is retarded in the alloys containing TaC.