In-situ TEM-heating study of the microstructural evolution of CrFeCoNiCu high entropy alloy (HEA) thin films was carried out and morphological and phase changes were recorded. Post annealing investigation of the samples was carried out by high resolution electron microscopy and EDS measurements. The film is structurally and morphologically stable single phase FCC HEA up to 400 °C. At 450 °C the formation of a BCC phase was observed, however, the morphology of the film remained unchanged. This type of transformation is attributed to diffusionless processes (martensitic or massive). From 550 °C fast morphological and structural changes occur, controlled by volume diffusion processes. Fast growing of a new intermetallic phase is observed which contains mainly Cr and has large unit cell due to chemical ordering of components in direction. The surface of the films gets covered with a CrO-type layer, possibly contributing to corrosion resistance of these.

Polymeric composites were prepared using ethylene-vinylacetate (EVA) matrix and expanded graphite (EG). Mechanical properties were investigated and it was found that Young's modulus and the yield stress of EVA-EG composites significantly increased with graphite content. However, for higher EG content the composites became brittle. The dependence of stress at the break of composites reached maximum at 30 vol.% of the filler. The morphology of both EG filler and composites were investigated using transmission electron microscopy and Raman spectroscopy. All these structural characterizations indicated partial exfoliation of EG within EVA matrix, which leads to the increase of the reinforcement effect.