Chemical, microstructural and nanoindentation characterization in nanocrystalline Ni-Fe alloys: experimental and numerical methods.

Research in nanocrystalline materials is growing due to their peculiar mechanical and functional properties. In this thesis, four samples of DC electrodeposited Ni-Fe alloys are considered, with different thickness and heat treatment history. A numerical simulation of nanoindentation test with Berkovich indenter has been implemented. Nanoindentation tests have been performed, both on top and cross section surfaces of the specimen, to investigate room temperature creep and understand the influence of sample thickness, peak load and hold time on such behaviour. Chemical and microstructural analysis, namely EDS, EBSD and EELS alongside SEM and TEM observation, have been carried out on as deposited and annealed samples, both with and without indentation mark, to gain knowledge on composition, orientation and possible deformation mechanisms in nanocrystalline Ni-Fe. Numerical simulation has been developed as a 3D model and specific geometries have been introduced in order to partialize the problem and save on computation cost.