Analysis of γ1 shape changes in a single crystal Ni-Base superalloy

Abstract

Analysis of γ¹ shape changes in a “commercial” nickel-base single crystal superalloy, NASAIR 100, was performed using a novel microstructural lattice model, MCFET. A negative mismatch of −0.3% and a modulos ratio (Eγ¹/Eγ) of 1.12 were used in the analysis. These values were based on actual high temperature measurements for NASAIR 100. Under a uniaxial stress, a regular array of γ¹ particles in the simulated microstructure was predicted to coalesce and form a plate morphology in which the broad faces of the plates and stress axis were perpendicular in tension but parallel in compression. These results were consistent with γ¹ shape changes observed in NASAIR 100 after creep testing at 1000C.