The aim of the present work was the preparation and characterization of FeSiB amorphous magnetic ribbons with the following chemical composition: Fe80SixB20-x, x=5,6,8 and Fe75Si15B10. Differential Scanning Calorimetry was employed in order to study the thermal stability and structural changes during the transformations that took place. Much emphasis is placed on the analysis of the crystallization kinetics.

The Barkhausen noise technique (BHN) has been used as a non destructive tool for the measurement of the hardness in various types of steel, namely low carbon steel, TRIP steel, Duplex steel and welding in low carbon steel. The steel samples have undergone different mechanical treatment, such as plastic deformation, cold rolling or welding. Hardness and microhardness have been determined in terms of Vickers standards. A remarkably linear dependence of the BHN on the Vickers hardness of the corresponding samples with an uncertainty in the order of 3-5% has been achieved, illustrating that the BHN may be used as a non destructive tool for determining the Vickers hardness in steels. Furthermore, BHN measurements have obtained on the welding area, along the thermally affected zone and the weld itself, illustrating the theoretically expected stress field distribution.

The aim of this study is to contribute to a better understanding of the dependence between Magnetic Barkhausen Noise and the plastic deformation of TRIP 800 steel samples. The TRIP 800 steel samples were subjected to increasing deformation by means of tensile loading and, meanwhile, Magnetic Barkhausen Noise parameters were measured (online measurements). Magnetic Barkhausen Noise parameters were, also, measured after the tensile deformation (offline measurements). The microstructure of the samples was studied by using Scanning Electron Microscopy and, finally, micro hardness and macro hardness measurements took place.

The aim of this study is to contribute to a better understanding of the properties, structure and crystallization process of the amorphous Fe-based ribbon with the following chemical compositions: Fe80SixB20-x (x=5,6,8) and Fe75Si15B10. Thermal analysis, including Differential Scanning Calorimetry and Magnetic-Thermogravimetric Analysis, were used to shed light in the thermal stability and structural changes taking place during the transformation from the amorphous state to the crystalline state. The arising microstructure was observed via X-ray diffraction. Finally, Magnetic Barkhausen Noise measurements took place so as conclusions to be derived relevant to the dependence between the parameters of the Magnetic Barkhausen Noise and the chemical composition of the amorphous ribbons.