Comparative study of electron and laser beam surface alloying

High intensity energy fluxes, such as electron beams and laser beams are widely used for surface alloying of metals and alloys. These technologies are able to cause the formation of the so called melt pool where the alloying elements interact each other. It is known that the homogenization of the surface alloy can be explained by intense Marangoni convection, caused by the high temperature gradient in the melt pool. The convection is inversely to the speed of the specimen motion during the alloying process and therefore, the choice of low alloying velocity will reflect on more homogeneous structure of the obtained alloy. In this study, a comparison of the structure and properties of electron and laser beam surface alloying of aluminium with niobium was conducted. The phase composition of the alloyed layers was determined by XRD (X-ray diffraction) with CuKα radiation. The microstructure was studied by SEM (Scanning Electron Microscopy). Chemical analysis was carried out using an EDX electron probe microanalyser. The microhardness of the obtained samples is also measured and compared with respect to the technology of the formation of each surface alloy.