  A Crystal Plasticity Finite Element (CPFE) framework is proposed for modeling
the non-Schmid yield behavior of L12 type Ni3Al crystals and Ni-based
superalloys. This framework relies on the estimation of the non-Schmid model
parameters directly from the orientation- and temperature-dependent
experimental yield stress data. The inelastic deformation model for Ni3Al
crystals is extended to the precipitate phase of Ni-based superalloys in a
homogenized dislocation density based crystal plasticity framework. The
framework is used to simulate the orientation- and temperature-dependent yield
of Ni3Al crystals and single crystal Ni-based superalloy, CMSX-4, in the
temperature range 260-1304 K. Model predictions of the yield stress are in
general agreement with experiments. Model predictions are also made regarding
the tension-compression asymmetry and the dominant slip mechanism at yield over
the standard stereographic triangle at various temperatures for both these
materials. These predictions provide valuable insights regarding the underlying
(orientation- and temperature-dependent) slip mechanisms at yield. In this
regard, the non-Schmid model may also serve as a standalone analytical model
for predicting the yield stress, the tension-compression asymmetry and the
underlying slip mechanism at yield as a function of orientation and
temperature.
