The influence of heat treatment on the corrosion properties of the aluminium alloy AA6005A

V avtomobilski in gradbeni industriji se kaže vedno večje povpraševanje po zlitinah z visoko korozijsko odpornostjo in primernimi mehanskimi lastnostmi. Za doseganje teh lastnosti se stremi po izdelavi najprimernejših zlitin. Zlitina 6005A je predvidevana kot primerna za doseganje ustreznih mehanskih in korozijskih lastnosti. Zlitini 6005A smo določili temperaturo umetnega staranja 170 °C, in čas staranja, od 2 do 22 ur. Opazovali smo potek razvoja mikrostrukture, izvedli natezni test, elektrokemično impedančno spektroskopijo, ciklično polarizacijsko metodo in specifično električno prevodnost. Zlitina je kazala najboljše mehanske lastnosti med 12. in 14. uro staranja, sorazmerno je naraščala tudi specifična električna prevodnost in korozijski potencial. Med 12 in 22 ur staranja so te lastnosti počasi upadale. Z ustrezno toplotno obdelavo je zlitina dosegala željeno korozijsko odpornost in visoke mehanske lastnosti, kot je bilo zahtevano. V času staranja smo v mikrostrukturi opazovali izločevanje faze Mg2Si, ki se izloča med toplotno obdelavo. Z doseženimi najvišjimi mehanskimi lastnostmi se je izločil tudi največji delež faze Mg2Si. Izločki so bili zelo drobni in homogeno porazdeljeni po kristalnem zrnu. S podaljševanjem časa staranja nad 12 ur se je začelo Ostwaldovo zorenje. Ta pojav slabo vpliva na mehanske in korozijske lastnosti materiala.In the automotive and construction industries, there is an increasing demand for alloys with high corrosion resistance and suitable mechanical properties. In order to achieve these properties, there have been endeavours to produce the most applicable alloys. The 6005A alloy is intended to be suitable for achieving the appropriate mechanical and corrosion properties. Therefore, the temperature of artificial aging, 170 ° C, and the aging time, from 2 to 22 hours were determined for the 6005A alloy. We observed the development of microstructure, performed tensile test, electrochemical impedance spectroscopy, cyclic polarization method and specific electrical conductivity. The alloy showed the most optimal mechanical properties between 12th and 14th hour of aging, and the specific electrical conductivity and corrosion potential increased proportionally. Between 12 and 22 hours of aging these features slowly declined. By a suitable heat treatment, the alloy achieved demanded corrosion resistance and high mechanical properties, as required. During the aging period, the Mg2Si phase separation was observed in the microstructure, which is eliminated during the heat treatment. With the highest mechanical properties achieved, the highest proportion of the Mg2Si phase was eliminated. The excrements were very tiny and homogeneously distributed over the crystalline grain. With an extension of aging time above 12 hours, Ostwald ripening began, the phenomenon that affects the mechanical and corrosion properties of the material