Structure of the alloys and the phase equilibrium diagram of the Zr-Ru-Ir system. IV. The projection of the solidus surface of the partial system Zr-ZrRu-ZrIr

The results of an investigation of the solidus surface of the second partial system of the ternary Zr-Ru-Ir-Zr-ZrRu-ZrIr system are presented. In the Zr-Ir system there exist four intermediate phases. For investigating the phase equilibria in the Zr-ZrRu-ZrIr system, alloys of 36 compositions were prepared by arc melting in argon. Under arc melting conditions, the majority of the alloys crystallized in a very nonequlibrium condition, as the result of which in the latter stage of the process they contained a relatively low-melting constituent. The alloys were investigated in the cast and annealed conditions by metallographic, hardness, x-ray diffraction, local x-ray spectral, and differential analyses. Temperature of the start of melting was determined by the Pirani-Altertum method. Illustrations show the isothermal section of the Zr-ZrRu-ZrIr system. In accordance with the solidus temperatures only four of the alloys investigated are found in the solid state while at 12000C only the alloys lying close to the isothermal plane of the solidus surface at 11750C remain in the liquid state