2510 KB16 KB200020242014Novák, PavelPrůša, FilipVoděrová, MilenaVojtěch, Daliborletnik:48številka:5str. 771-775COBISSID:1097386ISSN:1580-2949URN:URN:NBN:SI:doc-8NCTXHJBenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealuminijeve zlitinealuminium alloyaluminium alloysmelt spinningmicrostructuremikrostrukturaprehodne kovinesolidificationstrjevanjetransition metalsulivanje na bakreni valjMicrostructures of the Al-Fe-Cu-X alloys prepared at various solidification rates| Mikrostruktura zlitin Al-Fe-Cu-X po različnih hitrostih strjevanja|Aluminium alloys are usually prepared with conventional casting, but rapid-solidification methods lead to the alloys with better mechanical properties or thermal stability. When an improved thermal stability is required, aluminium is alloyed with one or more of the elements from the group of transition metals (TM), for example, Ni, Fe, Cr or Ti. These elements are characterized by a low diffusivity and solubility in aluminium even at elevated temperatures, while Cu in an alloy forms a CuAl2 phase that enables precipitation hardening. In this work, the microstructures of the Al-7Fe-4Cu, Al-4Fe-4Cu-3Ni and Al-7Fe-4Cu-3Cr (mass fraction, w/%) alloys prepared with various solidification processes were investigated. The aim of this work was to determine the changes in the microstructure caused by the increasing solidification rate and to determine the influence of the copper present in each alloy. All the samples were prepared with single-roll melt spinning, water quenching of the melt and conventional casting. The microstructures of the alloys were studied with light and scanning electron microscopy (SEM). The phase composition was determined with X- ray diffraction (XRD). Vickers hardness (HV 5) and microhardness (HV 0.005) were measured to compare the mechanical properties of the alloys. The microstructure and the hardness of the alloys strongly depended on the solidification rate. The fine microstructure and high microhardness values obtained with melt spinning are promising for the use of these alloys in special applications at elevated temperaturesZlitine aluminija se najpogosteje izdelujejo z navadnim ulivanjem, vendar pa metode hitrega strjevanja povzročijo nastanek zlitin z boljšimi mehanskimi lastnostmi ali toplotno stabilnostjo. Kadar se zahteva toplotna stabilnost, se aluminij legira z enim ali dvema elementoma iz skupine prehodnih kovin (TM), na primer: Ni, Fe, Cr ali Ti. Značilno za te elemente je majhna difuzivnost in topnost v aluminiju celo pri povišanih temperaturah, medtem ko Cu v zlitini tvori fazo CuAl2, ki omogoča izločevalno utrjanje. V tem delu so preiskovane mikrostrukture zlitin Al-7Fe-4Cu, Al-4Fe-4Cu-3Ni in Al-7Fe-4Cu-3Cr (masni deleži, w/%), pripravljenih z različnimi postopki strjevanja. Namen tega dela je bil opredeliti razlike v mikrostrukturi, ki jih povzroči povečanje hitrosti strjevanja, in opredeliti vpliv bakra v vsaki od navedenih zlitin. Vsi vzorci so bili pripravljeni z ulivanjem tankega traku na bakren valj, z ohlajanjem v vodi in z navadnim ulivanjem. Mikrostruktura zlitin je bila pregledana s svetlobnim mikroskopom in z vrstičnim elektronskim mikroskopom (SEM). Sestava faz je bila določena z rentgensko difrakcijo (XRD). Trdota HV 5 in mikrotrdota HV 0,005 sta bili izmerjeni za primerjavo z mehanskimi lastnostmi zlitin. Mikrostruktura in trdota zlitin sta močno odvisni od hitrosti strjevanja. Drobnozrnata mikrostruktura in velika mikrotrdota, dobljeni z ulivanjem na valj iz bakra, sta obetajoči za uporabo teh zlitin v posebnih primerih pri povišanih temperaturahTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije