Abstract: The present invention is a method for densifying powder metallurgical parts to 100% theoretical density. The method comprises applying a high pressure of 0.1-100 MPa during sintering in a high pressure furnace at a temperature before which the liquid phase is formed and maintaining this pressure during the rest of the sintering cycle until the furnace has cooled to almost room temperature. The method achieves rapid, complete closure of the porosity which results in parts with close dimensional tolerances and practically no warpage.

Abstract: A process for the preparation of an extrahard material based on tungsten and molybdenum carbides and having a hexagonal crystal structure identical with that of tungsten carbide. According to this process, one heats between 1000.degree. C. and a temperature T.sub.x, which is lower than the maximum stability limit of the Mo.sub.x W.sub.l-x C phase wherein 0.01.times.1, a mixture, intimate to the molecular or atomic scale, of tungsten and molybdenum the total content of which in Fe, Ni and Co does not exceed 0.1% with carbon and/or a carbon compound.T.sub.x is defined as follows:For 0.01<.times.<0.8, T.sub.x =2700-1375x.degree.C;For 0.8<.times.<1, T.sub.x =3400-2250x.degree.C.