Design of BCC—B2 Refractory Multi-principal Element Alloys

Refractory multi-principal element alloys show promise for high temperature structural applications beyond 1200 deg C. However, many single phase solid solution refractory MPEs do not retain a high level of strength beyond 1200 deg C. We show that in Ru-containing MPEs, strengthening is possible with Ru-containing B2 precipitates that are stable above 1200 deg C. The design and screening approach for identification of promising B2 – BCC matrix combinations will be described. Microstructures and properties in alloys containing RuHf, RuAl and RuTi B2 precipitates will be presented. Control of misfit to achieve coherent precipitates is demonstrated. Finally, implications for processing these alloys will be discussed.