High temperature phase diagrams of Re-U, Ta-U, and W-U

The accuracy of determining the solidus and the liquidus boundaries of binaries in which one of the components is high melting point metal could be improved with the use of the spot method proposed by Ackermann and Rauh. In this method, one makes use of the sudden change in the reflectivity and emissivity of the liquid phase. A dark spot appears at the first formation of the liquid phase, which gives the solidus temperature of the alloy. The temperature at which several of the dark spots coalesce into one single spot on further heating gives the corresponding liquidus temperature. This method was combined with the determination of the solubilities along the liquidus to obtain the high temperature phase diagrams of the Re-U, Ta-U and W-U systems. (orig.)