Mechanical behaviour of alloys containing heterogeneously distributed particles: modelling with Delaunay triangulation

Non-shearable precipitates and second-phase particles are efficient obstacles to dislocation motion that have an important effect on the strength and creep resistance of many materials, in particular oxide-dispersion-strengthened alloys. When the obstacles are clustered, the material cannot be considered as a homogeneous medium. Modelling its mechanical behaviour by means of constitutive laws requires an additional step of homogenisation. We propose here a new method based on the Delaunay triangulation of the obstacle distribution and compare it with a previously developed technique based on the Voronoi tessellation. The Delaunay triangulation is considered to be a better representation of local particle arrangement. It is shown that the softening effect of particle clustering is accentuated in the Delaunay triangulation approach.