Modelling at the dislocation level the reinforcement of alloys by hard precipitates: The example of Ni-base superalloys

Abstract

Experiments show that the strength of Ni-base superalloys strongly depends on the actual morphology of the y/y' microstructure. This makes a multiphase micro-mechanical modelling indispensable for a reliable safety analysis. Unfortunately, the classical crystal plasticity theory leads to erroneous predictions, when applied to the scale of the y/y' microstructure. This paper suggests that this failure is related to a breakdown of the meaning of plastic strain at the scale of the size of dislocation loops. We propose a global modelling of the y/y' compound that overcomes the deficiencies of local crystal plasticity at this description level.