20.500.12556/RUL-127266 Energy density effect of laser alloyed TiB$_2$/TiC/Al composite coatings on LMZ/HAZ, mechanical and corrosion properties In the present work, TiC/TiB$_2$/Al composite coatings were synthesized onto a precipitation hardened AlSi1MgMn alloy by laser surface alloying (LSA), using 13.3 J/mm$^2$ and 20 J/mm$^2$ laser energy densities. Microstructure evaluation, microhardness, wear and corrosion performance were investigated and compared with the untreated/substrate Al alloy sample. The results confirmed sound, compact, crackles composite coating of low porosity, with a proper surface/substrate interface. Microstructural analyses revealed the formation of extremely fine nano-precipitates, ranging from of 50–250 nm in the laser melted (LMZ) and large precipitates, accompanied with grain coarsening in the heat-affected zone (HAZ), due to the substrate overheating during the LSA process. Nonetheless, both coatings achieved higher microhardness, with almost 7-times higher wear resistance than the untreated sample as a consequence of high fraction volume of hard, wear resistant TiB$_2$ and TiC phases inside the composite coatings. Further, cyclic polarization results in 0.5 M NaCl aqueous solution confirmed general improvement of corrosion resistance after LSA processed samples, with reduced corrosion current by more than a factor of 9, enhanced passivation/repassivation ability and complete prohibition of crystallographic pitting, which was detected with the untreated Al alloy. laser surface alloying (LSA) ceramic coatings on Al alloy microstructure laser melted/heat affected zone (LMZ/HAZ) microhardness wear corrosion lasersko legiranje površine keramične prevleke aluminijeve zlitine mikrostruktura mikrotrdota obraba korozija true false true Angleški jezik Slovenski jezik Članek v reviji 2021-06-01 08:47:36 2021-06-01 08:47:39 2022-09-06 03:50:26 0000-00-00 00:00:00 2020 0 0 19 str. iss. 3, art. 411 Vol. 10 2020 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 620.1/.2:621.7+621.9(045) 2075-4701 10.3390/met10030411 17102363 RAZ_Ravnikar_Dunja_2020.pdf RAZ_Ravnikar_Dunja_2020.pdf 1 7C478C09A25FDE685C607CF5169870E5 da7c1f1807943885ae90dc1331cdc003820b31b1961b7731b6d2495d5febfc80 9f1ca670-4eb4-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=151505 https://www.mdpi.com/2075-4701/10/3/411 0 2fc3e2ae-c2a5-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=143579 Fakulteta za strojništvo Naravoslovnotehniška fakulteta 0 0 0