Recent studies of thermionic space nuclear power systems have led to the development of high temperature refractory alloys. One of the main problems with the use of polycrystalline materials at high temperature is the evolution of their microstructure. The strengthening mechanism employed for the single crystalline refractory alloys is mainly solution strengthening which is thermodynamically stable. The absence of grain boundaries in the single crystalline structure results in further stability. These attributes lead to superior mechanical properties over long periods of time. Work in this area in the past decade has identified Mo-based and W-based materials (in the polycrystalline as well as the single crystalline forms) to be the acceptable candidates for space nuclear applications. These phenomena is the subject of detailed discussion of the paper with frequent references and comparisons with other engineering materials. Special effort will be made to elucidate how high temperature commercial systems can benefit from the development of such single crystalline materials and their potential challenges for implementation.
The significance of the single crystalline structure in refractory alloys for high temperature applications
Die Bedeutung der monokristallinen Struktur in Hochtemperaturlegierungen
1995
6 Seiten, 6 Bilder, 3 Tabellen, 28 Quellen
Conference paper
English
Applications of refractory metals and their alloys
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