Experimental validation of residual stress thermomechanical simulation in as-quenched superalloy discs by using diffraction and incremental hole-drilling methods

Abstract

Mechanical properties of commercial Ni-based superalloys at elevated temperature rely strongly on the cooling rate during solution heat treatment. Quenching-induced residual stress can be crucial to machining accuracy and fatigue strength of industrial superalloy components.In this study, an existing finite-element-based methodology is improved by inverse heat transfer calculation and phase transformation latent heat input, with a maximum temperature deviation of ∼44℃. The simulated thermal stress and strain rate evolution demonstrate the origin of the quenching stress field. Robust non-destructive methods, i.e., neutron diffraction and X-ray diffraction, are employed to validate the simulated surface and internal residual stresses in both air-cooled and water-quenched discs. The simulated in-depth normal residual stress profiles are proven to be consistent with the results of non-destructive measurement, with a maximum average deviation of ∼34 MPa. After a rapid quenching process, the near-surface stress gradient measured by incremental hole-drilling method at a depth of 0.45 mm is ∼150 % lower than simulation result.