Microstructural evolution and mechanical properties of Cr-Ru alloys

In an effort to enhance ductility and strength of Cr-base alloys, a series of Cr-Ru alloys with Ru contents ranging from 3 to 30 at. pct were made to study their microstructure evolution and mechanical properties. The microstructure of the alloys with 6 to 20 at. pct Ru showed signs of a eutectic structure. However, no corresponding eutectic reaction is indicated in the published Cr-Ru phase diagram. The yield strength of the Cr-Ru alloys increased with increasing Ru content at both room temperature and 1200 °C. The tensile ductility of Cr-3 at. pct Ru is about 1.5 pct at room temperature, while the alloys containing 6 at. pct or more Ru showed zero tensile elongation. The deformation mechanisms of the Cr-Ru alloys are discussed in terms of the microstructure and fracture behavior. This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory Metals Committee.