Abstract
The results of an exploratory study of eutectics based on Ni-25Cr–15Ti (wt %)and Co-10Cr-32Mo compositions will be presented. These alloys were selected from a total of ten different eutectic systems, all having melting points above 1200°C, a specific gravity less than 9,000 kg/m3, and a parabolic oxidation rate below 10−7 g2 · cm−4 · s−1 at 1150°C as reported by Haour, Mollard, Lux, and Wright on work done at Battelle-Geneva Research Centre. The Ni-25Cr-15Ti eutectic appeared to have a high volume fraction of ductile chromium fibers in a brittle Ni3Ti matrix. This alloy although the strongest of the six alloys that have been tested from the group reported by Battelle is still not competitive with advanced superalloys. Its tensile strength at 1093°C was 227 MPa2 and its elongation was 14%. The Co-10Cr-32Mo eutectic had the highest melting point (1340°C) of the alloys screened by Battelle. It appeared to solidify in a basically bladelike or lamellar structure, consisting of the intermetallic μ phase in a metallic Co (Cr) matrix. The strongest of the Co-Cr-Mo eutectics tested had a tensile strength of 164 Mpa and an elongation of 15% at 1093°C. The correlation observed between the strengths of the Ni-Cr-Ti and Co-Cr-Mo alloys, compositional variations, and their microstructures will be discussed.
Publisher
Springer Science and Business Media LLC