LASER MICROSTRUCTURE MODIFICATION OF ALUMINUM-ALLOYS AND STEELS

Structure changes in laser modified surface layers of aluminium alloys : Al-Zn, Al Fe, Al-Fe-Ni and steels: X45CrSi93, C50, as well as high s peed steel S 6-5-2 are studied after laser remelting and laser alloyin g by means of carbide (VC) and borides (CrB, VB2). The significant str ucture refinement and formation of characteristic precipitates for rap idly quenched microstructures are stated in aluminium based alloys. Fi ne microstructure with martensite is observed in constructional steels . Laser alloying of S 6-5-2 results in microstructure variation and ap pearance of new types of precipitates enriched with W, Cr, and V. The microstructure features are discussed in relation to the stated increa se of hardness in all the cases of laser modification.