Welcome to "Refractory Superalloys" page!

• Ir alloys (Ir-Nb, Ir-Ti, Ir-Ta, Ir-V, Ir-Zr and Ir-Hf)
• Rh alloys (Rh-Nb, Rh-Ti and Rh-Ta)

Development of Ir-based refractory superalloys:Strength of Ir binary alloys
Development of Rh-based refractory superalloys:Strength of Rh binary alloys
Design of quaternary refractory superalloys
Precipitation hardening and dislocation structure of Ir-based refractory superalloys :Deformation behavior of Ir-based binary alloys :Comeing soon!
Strength behavior of Ir based L1₂ intermetallics :Comeing soon!
Fracture mode of Ir-Nb binary alloys :Comeing soon!
Effect of Ni addition for mechanical properties of Ir-Nb alloys :Comeing soon!

What is "Refractory Superalloys"?

Refractory Superalloys have good potensials to be next generation high temperature materials. They can be used at high temperatures where Ni-based superalloys can not be used, because melting temperatures of base metals are higher than that of Ni (1453 degree C).

Why are superalloys so strong at high temperatures?

It is known that Ni-based superalloys, which can be used as turbine blades and vanes in jet engines of airplanes or gas turbines of power generators, have extremly high strengths at high temperatures because of the fcc and L1₂ coherent two phase structure. The coherent interface prevents movement of dislocations. We thought that if the fcc and L1₂ coherent two phase structure is formed in the alloy with a higher melting temperature than that of Ni, the alloy will be stronger than Ni-based superalloys. We selected platinum group metals as base materials for refractory superalloys.

Base materials: Platinum Group Metals

Platinum Group Metals (Ir, Rh, Pt, Pd, Os and Ru) are promissing materials for base metals of refractory superalloys because of their high melting temperatures and superior oxidation resistance. Ir, Rh, Pt and Pd have the fcc structure similer to Ni, although Os and Ru have the hcp structure. Ir and Rh (fcc) can be equilibrated with the L1₂ structure (see Phase diagrams). Thus we are investigating Ir- or Rh-based refractory superalloys.