A New Understanding of Creep in Superalloys

August 31, 2020
A New Understanding of Creep in Superalloys
(a) Sample under load at high temperatures during neutron experiment. (b) Experimental and predicted back-stress evolution during primary creep.

Scientific Achievement

A theory-derived equation predicting stress re-distribution during primary creep in  strengthened Ni-base superalloys was developed and verified experimentally.

Significance and Impact

Creep deformation and failure are important damage modes in Ni-based superalloys used widely in gas turbines. A more accurate prediction of primary creep in such particle-strengthened materials will better guide alloy design and improve component life.

Research Details

  • The theory shows that long-range stress within the matrix (“back-stress”) can be estimated from creep experiments if phase-specific elastic strains are obtained from in-situ neutron diffraction experiments.
  • GE’s DS GTD-111TM and GTD-444TM superalloys were mounted in a load frame and inductively heated during the in-situ neutron experiment.

“Back-Stress and Its Evolution during Primary Creep in Particle Strengthened Nickel Superalloys”
Sanket Sarkar, Yan Gao, Shenyan Huang, Saswata Bhattacharya, Swapnil Patil and Ramkumar Oruganti,
Crystals, 10(4), 306 (2020). DOI: https://www.mdpi.com/2073-4352/10/4/306