24 KB307 KB23 KB200020242004Aleksić, RadeBosnjak, BrankaFilipović, MirjanaNikolić, SlobodankaRadonjić, BranislavValčič, AndrejaZlatičanin, Biljanaštevilka:1/2letnik:387 stranistr. 25-31ISSN:1580-2949COBISSID:341418URN:URN:NBN:SI:doc-I6KRMMY0enInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealuminijaluminumbakerfazemagnezijstrjevanjestrukturetrdnosttrdotazlitineThe effect of magnesium and titanium additions on the microstructure and properties of as-cast Al-5 % Cu alloys|The effect of the mass fraction of magnesium content in the range 1-5 %, on the microstructure and properties of Al-Cu-Mg alloys (with a copper content of 5 %) was examined. The as-cast microstructure was modified by the addition of AlTi5B1 to obtain 0.25 % of titanium in the alloys. Using X-ray powder diffraction we established that the tetragonal intermetallic compound Alsub(2)Cu and the orthorhombic intermetallic compound Alsub(2)CuMg are formed across the whole range of magnesium additions. The effect of magnesium and titanium contents on the microstructure was monitored quantitatively using automatic image analysis to measure the linear intercept grain size, the secondary dendrite arm spacing (DAS), the size of the eutectic cells (Le), as well as the size distribution and the volume fractions of the alpha-solid solution and the eutectic. In alloys with a high magnesium content the average values of the DAS and the grain size were found to decrease. In contrast, with a lot of magnesium the average eutectic cell length and the eutectic volume fraction were found to increase. The changes inthe chemical composition of the alloy cause changes in the microstructure that are reflected in the Brinell hardness and the compression strength. The compression strength and hardness increase with the content of magnesium and titaniumRaziskan je vpliv masnega deleža magnezija v razponu od 1 % do 5 % na mikrostrukturo in lastnosti zlitin AlCuMg s 5 % bakra. Strjevalna mikrostruktura je bila modificirana z dodatkom AlTi5Bi1 s ciljem doseči v zlitinah vsebnost 0,25 % titana. Z uporabo rentgenske difrakcije je bilo ugotovljeno, da nastajata v vsem območju dodatkov magnezija tetragonalna intermetalna faza Alspodaj(2)Cu in ortorombična faza Alspodaj(2)CuMg. Vpliv magnezija iz titana na mikrostrukturo je bil kvantitativno ocenjen z avtomatsko analizo slike in določene so bile: linearna intercepcijska dolžina, širina sekundarnih dendritnih vej (DAS), velikost evtektičnih celic (Le) in velikostna porazdelitev ter volumenski delež trdne raztopine alfa. V zlitinah z visokim magnezijem sta bila manjša DAS in velikost zrn, medtem ko sta bila večja povprečna velikost evtektičnih celic in volumenski delež evtektika. Spremembe v kemični sestavi in mikrostrukturi se izražajo v trdoti po Brinellu in v tlačni trdnosti, ki rasteta s povečanjem vsebnosti magnezija in titanaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije