Faculty Mentor

Dr. Rick Ubic

Subject Area



Alloy 617, a nickel‑based alloy, is a leading candidate for application in next‑generation nuclear plants (NGNPs). Creep, a thermally activated, time-dependent deformation process impacts the lifetime and failure of heat exchangers used at the very high operating temperatures and pressures of such plants. Current methods of testing creep are generally limited to bar specimens in uniaxial tension. In an attempt to correlate uniaxial to multiaxial creep behavior a method to test creep in a pressurized tube was developed. Test specimens were pressurized with argon up to 3.5 MPa, and heated to 950°C. Creep rates were measured as strain rates by tracking diametric changes with time. Parallel experimental and modeling efforts were used to characterize creep behavior in the pressurized tubes. The aim of this research was to use the existing body of knowledge concerning creep in Alloy 617 to develop a model to accurately predict creep in tubular components. Towards this end, a constitutive model was developed and computer simulations undertaken which were ultimately verified experimentally.


Alloy 617, creep, next generation nuclear plant, pressure vessel, very high temperature reactor