Structural Features of Cast Refractory Alloy HP40NbTi High-Temperature Oxidation. Part 2. Microstructure and Phase Composition Evolution

Optical and electron microscopy and x-ray spectral microanalysis are used to study the transformation of the phases present in the structure of cast refractory alloy HP40NbTi during prolonged high-temperature oxidation. It is established that during oxidation alloy phase chemical composition changes continuously and by complex laws in relation to the surroundings, temperature, and exposure duration, and there is rapid exchange of chemical elements between different phases. After prolonged exposure this process reaches a limiting condition.