Wire Arc Additive Manufacturing of aluminium alloy AlSi5 using TIG process

Oblikovno obločno navarjanje (angl. Wire Arc Additive Manufacturing (WAAM)) uvrščamo med novodobne aditivne tehnologije za izdelavo kompleksnih 3-dimenzionalnih kovinskih produktov. Sistemi za navarjanje so običajno sestavljeni iz že obstoječih varilnih in robotskih sistemov. V nalogi smo obravnavali lastnosti navarjenega materiala ter izvedli podrobne analize za vrednotenje. Material se navarja po plasteh, zato se lahko med njihovimi lastnostmi pojavijo razlike. Iz tega vidika je bilo potrebno v prvi fazi določiti ustrezne parametre za izdelavo sten. Iz sten smo nato glede na smer navarjanja izrezali horizontalne in vertikalne epruvete za preizkus natezne trdnosti ter analizo mikrostrukturnih značilnosti. Prelomne površine nateznih preizkušancev po porušitvi in mikrostrukture smo ovrednotili na optičnem mikroskopu. Rezultati analiz so potrdili, da smer odvzema in obremenjevanja vzorcev glede na smer gradnje ne izkazuje značilnih razlik. Ob tem je povprečna natezna trdnost v smeri navarjanja znašala 151,6± 5 MPa, pravokotno na smer navarjanja pa 144,1± 4 MPa. V navarjenih plasteh smo izvedli analizo poroznosti in velikosti dendritnih zrn v programu ImageJ. Ocenjena poroznost v spodnjih plasteh je znašala 6,8 %, v zgornjih pa 3,1 %. Povprečna velikost dendritnih zrn v navarjeni steni je znašala 55,7 µm.Wire arc additive manufacturing (WAAM) is one of the newest additive manufacturing technologies for the production of complex 3-dimensional metal products. Welding systems are usually composed of existing welding and robotic systems. In this thesis, the properties of the material to be welded are discussed and detailed analyses for evaluation are carried out. The material is welded in layers, so differences may occur between their properties. From this point of view, it was necessary in a first stage to determine the appropriate parameters for the wall fabrication. Horizontal and vertical tubes were then cut out of the walls according to the direction of welding for tensile strength testing and analysis of microstructural characteristics. The fracture surfaces of the tensile test specimens after failure and the microstructures were evaluated using an optical microscope. The results of the analyses confirmed that the direction of removal and loading of the specimens with respect to the direction of welding did not show significant differences. The average tensile strength in the direction of welding was 151,6± 5 MPa and perpendicular to the direction of welding was 144,1± 4 MPa. Porosity and dendrite grain size analysis was performed in ImageJ software. The estimated porosity in the lower layers was 6,8 %, in the upper layers 3,1 %. The average dendrite grain size in the wall was 55,7 μm