PHASE CONSTITUTION OF THE COBALT-RICH COBALT-VANADIUM ALLOY SYSTEM.

The phase relations of the Co-rich Co-V system in the range from approx. 10 to 23 at. % V has been examined in the temperature range from 600 to 1150 degree C by correlating the results of X-ray and electrical resistance measurements. The AuCu//3-like alpha //I phase was newly found to occur in a composition of 18 at. % V in the temperature range from about 700 to 860 degree C. The previously reported alpha //L phase of the AuCu//3-type structure was also confirmed in the composition range from 12. 4 to 22. 8 at. % V below the critical temperature of about 700 degree C. Although the X-ray powder photographs were unable to make any distinction between the alpha //I and alpha //L phases, the lattice parameter and electric resistance data revealed a subtle difference in the crystallographic nature between both phases. A phase diagram, modified so as to include the alpha //I and alpha //L phases in addition to the disordered fcc alpha //H phase, is proposed.