Microstructures of Ternary Eutectic Refractory Me-Si-B (Me = Mo, V) Alloy Systems

The present work addresses the microstructure evolution of refractory Me-Si-B (Me = Mo, V) alloys consisting of a refractory metal solid solution phase (MeSS) and two intermetallic phases Me5SiB2 and Me3Si. The aim of the present study is to find the ternary eutectic composition in such systems which are expected to combine a well-defined eutectic microstructure with properties such as high strength, an excellent creep resistance at high temperatures and acceptable oxidation behavior. Two refractory metal systems based on molybdenum and vanadium are investigated. Various alloy compositions located in different primary solidification areas were produced by arc-melting and analyzed via SEM. The obtained results are discussed in the light of published liquidus projections. By carrying out these experiments, a MeSS-Me5SiB2-Me3Si ternary eutectic could be determined in both Me-Si-B systems.