J. Phys. IV France
Volume 105, March 2003
Page(s) 131 - 138

J. Phys. IV France
105 (2003) 131
DOI: 10.1051/jp4:20030180

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

B. Fedelich

Bundesanstalt für Materialforschung und-Prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany

Experimentshow that the strength of Ni-base superalloystrongly depends on the actual morphology of the  $\gamma/\gamma'$ 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  $\gamma/\gamma'$ 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  $\gamma/\gamma'$ compound that overcomes the deficiencies of local crystal plasticity at this description level.

© EDP Sciences 2003