20.500.12556/DKUM-99399 Karakterizacija Al-zlitine EN AW-5454 namenjene za lasersko hibridno varjenje Characterization of Al-alloy EN AW-5454 intended for laser hybrid welding Lastnosti osnovnega materiala pomembno vplivajo na lastnosti varjenega sklopa, še posebno pri modernejših postopkih varjenja kot je lasersko hibridno (LH). Zaradi velikih hitrosti varjenja in s tem povezanimi višjimi hitrostmi strjevanja taline je zato zelo pomembno, da imajo za varjenje pripravljeni polizdelki čim manjši delež napak v zvarnem spoju, saj le-te znatno vplivajo na strukturno integriteto varjenega sklopa. Napakam v ulitkih se izognemo z ustrezno pripravo Al-taline, ki poteka v talilnih pečeh, izbrano tehnologijo ulivanja ter z nadaljnjo termo-mehansko obdelavo in predelavo v zahtevane oblike polizdelkov. Napake, kot so krčilna poroznost, ostanki oksidnih filmov in plinske pore, poslabšujejo mehanske lastnosti končne Al-zlitine, kot tudi njeno varivost. Nastale napake v Al-zlitini lahko pri varjenju povzročijo nastanek razpok v zvarnem spoju. Al-zlitini EN AW-5454, ki se utrjuje z deformacijo, se pri obdelavi spreminjajo njene mehanske lastnosti, kar je povezano z nastalo teksturo tako predelane Al-zlitine. V tej študiji je bila izvedena komplementarna karakterizacija osnovne Al-zlitine EN AW-5454, ki je namenjena za LH varjenje. Študija je vključevala mikrostrukturno analizo Al-zlitine in določitev njenih lastnosti (trdoto HV5, natezno trdnost, udarno žilavost, lomno mehanske sposobnosti). Vzorci so bili pripravljeni v vzdolžni in prečni smeri iz dveh Alpločevin z debelinama 4 in 3,5 mm. Mikrostrukturna analiza je pokazala, da so v osnovni α-matici obeh pločevin prisotni intermetalni delci Al6(Mn, Fe), ki so med testiranjem mehanskih lastnosti v vzdolžnih vzorcih ostali večinoma nespremenjeni, medtem, ko je pri prečnih vzorcih bila opazna njihova porušitev. Rezultati meritev trdote so pokazali, da imajo vzorci Al-zlitine iz tanjše pločevine ~5 % višjo trdoto v primerjavi z vzorci Al-zlitine iz debelejše pločevine. Natezna trdnost in meja tečenja sta bili v območju nominalnih vrednosti, pri čemer so bili raztezki manjši za 2,2–3,2 % (vzdolžno glede na smer valjanja) in 2,7–13,7 % (prečno glede na smer valjanja). Rezultati preizkusov udarne žilavosti po Charpy-ju so pokazali, da je potrebna energija preloma pri preizkušancih izdelanih v vzdolžni smeri (glede na smer valjanja) večja za ~20 % (4,0 mm) oziroma ~40 % (3,5 mm) kot pri preizkušancih izdelanih v prečni smeri (glede na smer valjanja). SENB (Single Edge Notched Bend) lomno mehanski preizkusi so pokazali, da je odpornost na rast razpoke pri vzdolžnih vzorcih ~50 % večja kot pri prečnih vzorcih. Vrstična elektronska mikroskopija (SEM) prelomnih površin je pokazala, da so se prelomne površine preizkusov udarne žilavosti po Charpy-ju razlikovale od tistih pri SENB lomno mehanskih vzorcih. Pri preizkusih udarne žilavosti po Charpy-ju so bili delci Al6(Mn,Fe) v vzdolžnih vzorcih pretežno ohranjeni z žilavimi območji, medtem ko so v prečnih vzorcih pogosteje zdrobljeni in usmerjeni v smeri valjanja z manj žilavimi območji. Pri SENB lomno mehanskih vzorcih so bili delci Al6(Mn,Fe) v vzdolžnih vzorcih bolj zdrobljeni kot pri preizkusih udarne žilavosti po Charpy-ju, v prečni smeri, pa so bili ti delci večinoma celi oziroma manj zdrobljeni. V vzdolžnih vzorcih je razporeditev delcev manj izrazito orientirana kot pri prečnih vzorcih. Odpornost proti širjenju razpoke je bila ~50 % večja pri vzorcih izdelanih vzdolžni smeri valjanja kot v prečni smeri valjanja. Ključne besede: Al-zlitina EN AW-5454, varjenje, lastnosti, karakterizacija, The properties of the base material significantly affect the properties of the welded assembly, especially in more modern welding processes such as laser hybrid (LH). Due to the high welding speeds and the associated higher melt-solidification rates, it is very important that the semi-finished products prepared for welding have the smallest possible number of defects in the weld joint, as these significantly affect the structural integrity of the welded assembly. Defects in castings are avoided by appropriate preparation of the Al-melt in melting furnaces, adequate casting technology, thermo-mechanical treatment and processing into the required shapes of the semi-finished products. Defects such as shrinkage porosity, oxide film residues and gas pores deteriorate the mechanical properties of the final Al alloy, as well as its weldability. The resulting defects in the Al alloy can cause cracks in the weld joint during welding. The mechanical properties of the EN AW-5454 Al-alloy, which is hardened by deformation, change during processing, which is related to the resulting texture of the processed Al-alloy. In this study, a complementary characterization of the basic Al alloy EN AW-5454, intended for LH welding, was performed. The study included microstructural analysis of the Al-alloy and determination of its properties (HV5 hardness, tensile strength, impact toughness, fracture mechanical properties). The specimens were prepared in the longitudinal and transverse directions from two Al sheets with thicknesses of 4 and 3.5 mm. The microstructural analysis showed that the basic α-matrix of both sheets contained intermetallic particles Al6(Mn, Fe), which remained largely unchanged during the mechanical properties testing in the longitudinal specimens, while their destruction was observed in the transverse specimens. Hardness measurements demonstrated that specimens produced from the thinner Alsheet exhibited approximately 5% higher hardness values compared to those from the thicker Al-sheet. Tensile strength and yield strength were within the nominal ranges, while elongations were lower by 2.2–3.2% in the longitudinal direction and by 2.7–13.7% in the transverse direction. Charpy impact tests showed that specimens machined longitudinally (with respect to the rolling direction) required approximately 20% more fracture energy for the 4.0 mm Al-sheet and approximately 40% more for the 3.5 mm Al-sheet compared to specimens machined transversely. SENB (Single Edge Notched Bend) fracture mechanics tests revealed that the resistance to crack propagation in the longitudinal specimens was approximately 50% higher than in the transverse specimens. Scanning electron microsce (SEM) fractography showed clear differences between the Charpy and SENB fracture surfaces. In the Charpy impact specimens, the Al6(Mn, Fe) particles remained largely intact in the longitudinal direction, accompanied by more ductile fracture features, whereas in the transverse direction, the particles were more frequently fragmented and aligned along the rolling direction, resulting in less ductile regions. In the SENB specimens, the Al6(Mn, Fe) particles in the longitudinal direction were more severely fragmented than in the Charpy specimens, while in the transverse direction they were generally intact or only slightly fragmented. The particle distribution in the longitudinal specimens was less directionally aligned compared to the transverse ones. The overall crack growth resistance was approximately 50% higher in the specimens oriented parallel to the rolling direction. Al-alloy EN AW-5454 welding properties characterization microstructure Al-zlitina EN AW-5454 varjenje lastnosti karakterizacija mikrostruktura true false false Angleški jezik Slovenski jezik Znanstveno delo 2026-08-15 06:50:49 2026-08-18 13:01:01 2026-08-19 03:07:32 0000-00-00 00:00:00 2026 0 0 str. 110-129 št. 2 Letn. 73 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.74:669.715 284433923 0024-5135 Karakterizacija_Al-zlitine_EN_AW-5-Balant-2026.pdf Karakterizacija_Al-zlitine_EN_AW-5-Balant-2026.pdf 1 C246BB63A4529531B38672C722388540 78e3180faf6888fcf9f4296af2887347bc88a4ad454f8e034333a8a6432b8f7d 3a175c8a-9af4-11f1-8356-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=209751 https://www.drustvo-livarjev.si/index.php?module=vestnik&op=show&vestnikId=100 0 72fc857a-9af4-11f1-8356-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=209752 https://www.dlib.si/stream/URN:NBN:SI:doc-4THH2KAO/4510107f-7148-462a-84b2-75183baca2ce/PDF 0 9e6936cb-9af4-11f1-8356-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=209753 Fakulteta za strojništvo 0 0 0