DEVELOPMENT STUDY OF HIGH-TEMPERATURE STRUCTURAL MATERIALS OF LAVES PHASE REFRACTORY ALLOYS WITH HIGH RESISTANCE TO CORROSION AND ENVIRONMENT

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The phase diagram of ternary Nb-Cr-Ti alloy systema at 1350℃ are investigated by mettallography, X-ray diffraction and transmission electron microscopy equipped with energy-dispersive X-ray analysis. And also, high temperature deformability is investigated by compression test. In the composition between 5at.%Nb and 15at.%Nb in the alloy with 66.7at.%Cr-(33.3-x)at.%Ti-x at.%Nb, C36 Laves phase with dihexagonal structure is in equilibrium to C15 phase with fcc structure at a temperature of 1350℃. And Laves phase are equilibrated directly with Cr-bcc solid solution without forming any intermetallic phases. The eutectic path consisting of Laves phase and Cr-bcc solid solution lies in a composition between 75at.%Cr and 80at.%Cr in the ternary Nb-Cr-Ti alloy system. Form the experimental result of compression test, the high-temperature deformability of the alloy consisting of primary Cr-bcc solid solution and Laves phase is better than that of the alloy consisting of primary Laves phase and Cr-bcc solid solution.