Deformation behaviour of particle-strengthened alloys: a Voronoi mesh approach

A modelling approach based on the discretisation of a particle-strengthened material using a Voronoi mesh is considered. The model is applied to studying the effects of particle arrangement on the deformation behaviour of a particle-strengthened alloy, particularly on its creep resistance. On a local scale, i.e. within an individual Voronoi cell containing a single particle, a dislocation density-based constitutive model developed previously is applied. Interaction with adjacent Voronoi cells due to plastic incompatibilities is also included. The model predicts a dependence of the creep resistance on the character of particle distribution, notably, on the degree of particle clustering. Application to oxide dispersion strengthened (ODS) nickel-base alloys MA 754 and PM 1000, which are very similar in their metallurgical characteristics, including the volume fraction of oxide dispersoids, but differ in the dispersoid arrangement, shows an excellent predictive capability of the Voronoi mesh modelling technique.