Thermodynamics of polycrystalline materials within the theory of mixtures with continuous diversity

We review the key steps in the formulation of a homogenisation procedure of a polycrystalline material in which crystal orientation and crystal size are two major ingredients of the microstructure. This is done within the context of rational thermodynamics of the Müller-Liu form. Only the basic concepts are given, leaving details to a talk by L. Placidi.