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Modern trends in research and development of new aluminum alloys are characterized in the present work. Although conventional wrought and casting Al-based alloys show good specific strength, as compared to steels or Ti-based alloys, there is still a potential for significant improvement of their performance. It consists in application of new alloying elements, mainly transition metals, and uncommon processing routes, for example powder metallurgy. By this way, qualitatively new materials with ultra high strength and excellent thermal stability can be developed. However, there are many questions to be answered before new alloys can be competitive to conventional Al-based materials., Članak daje karakteristike modernih stremljenja u istraživanju i razvitku novih aluminijskih legura. Mada konvencionalno oblikovane deformiranjem i ljevanjem Al-temeljne legure daju dobru specifičnu čvrstoću u usporedbi sa čelikom ili Ti-legurama, još postoje mogućnosti značajnijeg optimiranja njihovih svojstava. To se sastoji u rabljenju novih legirajućih elemenata, glavnih prijelaznih kovina i neobičajenih procesa, npr. praškaste metalurgije. Na taj način mogu se usavršavati kvalitetno novi materijali sa visokom čvrstoćom i izvanrednom termičkom postojnošću. Unatoč tome, ima više pitanja na koje treba dati odgovore prije nego nove legure mogu biti kompetentne s konvencionalnim Al-temeljnim materijalima.

The paper presents short characteristics of the most frequently used reactors for the continuous refining of aluminium and its alloys. Refining depends on the flow rate of refining gas. It influences the shape and size of gas bubbles. So the physical model was created to determine the level of gas bubble dispersion in liquids. Schemes of gas dispersion in liquid metal were presented taking into consideration that the gas flow rate is changing from 2 to 30 dm3/min. The range selection of the flow rate of refining gas value for five patterns of the dispersion (no dispersion, minimum, intimate, uniform and overdispersion) was also done., Članak daje kratke karakteristike najčešće rabljenih reaktora za kontinuiranu rafinaciju aluminija i njihovih legura. Rafinacija ovisi o brzini struje plina za rafinaciju. Utjecajni su oblik i dimenzije plinskih mjehura. Fizikalni model je utemeljen za određivanje razine disperzije plinskih mjehura u tekućinama. Shema disperzije plina u tekućem metalu predstavljena je uzimajući u obzir promjene brzina struje plina za rafinaciju vrijedeće za pet stupnjeva disperzije (bez disperzije, minimalna, očekivana, ujednačena i pojačana disperzija).

This work deals with the influence of alloying elements in aluminium on the grain refinement with various additions of AlTi5B1. Grain-refinement tests were made at a cooling rate of 15 °C/s. The results revealed that in both aluminium and an Al-Fe alloy the grain size decreases with increasing additions of the AlTi5B1 grain refiner. We found that for the same boron content the grain size was smaller in the case of the Al-Fe alloy. The difference in the grain sizes for the same content of boron was approximately 15 μm; this is considerably smaller than the difference between the grain sizes in samples with the same difference of growth-restricting factor made at slower cooling rates., Članak se bavi utjecajem legirajućih elemenata u aluminiju na usitnjavanje zrna s različitih dodatcima AlTi5B1. Ispitivanje usitnjavanja zrna je provedeno pri brzini hlađenja od 15 °C/s. Rezultati su otkrili da i u aluminiju i u Al-Fe leguri veličina zrna pada s povećanjem dodatka AlTi5B1 cjepiva. Utvrdili smo da je za isti dodatak bora veličina zrna manja u Al-Fe leguri. Razlika u veličini zrna za isti dodatak bora je bila približno 15 μm; što je značajno manje od razlike u veličini zrna u uzorcima s istom razlikom faktora ograničavanja rasta, pri manjim brzinama hlađenja.

SPD methods are used to convert coarse grain metals and alloys into ultrafine grained (UFG) materials. Obtained UFG materials then possess improved mechanical and physical properties which destine them for a wide commercial use. This paper, in one direction, looks into historical development of SPD processes and their effect at obtaining fine crystalline structure, and on the other side also partially focuses on development of UFG structure and its stability in commercial pure aluminium as a function of strain and post-deformation annealing applied., Obrada metala intenzivnom plastičnom deformacijom (IPD) – odgovarajuća struktura i mehanička svojstva. IPD je postupak pretvorbe krupno u ultrafino zrnate (UFZ-a) metale i legure. Dobiveni UFZ materijal posjeduje oplemenjena mehanička i fizikalna svojstva, te su namjenjeni za široko komercijalno rabljenje. Ovaj članak s jedne strane daje osvrt na povijesni razvitak IPD-a postupka, a s druge strane djelomice ishodište za razvitak UFZ-a i njezine stabilnosti u trgovački čistom aluminiju, kao funkcija preoblikovanja i poslije deformacije primjenjenog žarenja.

It was found that concentration of boron in aluminium with the addition of AlTi5B1 grain refiner is decreasing during remelting as a consequence of TiB2 particles settling down due to gravity. TiB2 particles remained in aluminium after four remelts shows lower effect of grain refinement compared to non-remelted samples with the same TiB2 content. It was also found that TiC particles are still present in aluminium with the addition of AlTi3C0,15 grain refiner after four remelts and they probably participate in nucleation of α-Al grains., Istraživanjem je utvrđeno da se s pretapanjem aluminiuma, kod dodavanja modifikatora AlTi5B1, koncentracija bora u leguri smanjuje, što je posljedica gravitacijske segregacije TiB2. Kod istog sadržaja čestica TiB2 u leguri, ima taj inokulant poslije četiri pretapanja, manji efekt na smanjenje velikosti kristalnih zrna, kao u primarno taljeni leguri. Isto tako je bilo ustanovljeno, da su u aluminiumu sa dodatkom AlTi3C0,15, i poslije četiri pretapanja još prisutne čestice TiC, koje vjerojatno sudjeluju u procesu nukleacije zrna α -Al.