Abstract
WC-Co alloys having 5∼25%Co and various carbon contents were vacuum-sintered and subsequently vacuum-annealed at 600°∼800°C for about up to 50 hr. Some properties of the sintered alloys affected by the annealing were studied noticing their carbon content. Results obtained are summarized as follows:—(1) After annealing, the hardness of alloys does not change; the rupture-strength decreases associated with the slight increase of hardness of binder phase; the lattice constant of the binder, and specific resistivity of the alloys decrease; the microstructure of the binder and its stability for acidic solutions change. (2) These changes in properties result from the precipitation of W atoms from the binder phase during annealing. (3) This is a reason why the properties of the alloys having a lower content of carbon, viz, a higher dissolved W in the binder phase, change remarkably.
