20.500.12556/DKUM-27836 Morfologija karbida MC in borida M3B2 v liti Ni-superzlitini GMR 235 Morphology of the MC carbide and the M3B2 boride in the as-cast Ni-based superalloy GMR 235 V tem delu smo raziskali morfologijo karbida MC in borida M3B2 v litem stanju nikljeve superzlitine GMR 235. Normalne in globoko jedkane metalografske vzorce ter tudi elektrolizno ekstrahirane karbide in boride smo opazovali predvsem na vrstičnem elektronskem mikroskopu. Zaradi značilnosti strjevanja te zlitine, ki se začne s primarno kristalizacijo trdne raztopine na osnovi niklja - faze y, sta se karbid in borid v glavnem nahajala v meddendritnem prostoru. Njuna velikost in oblika sta bili odvisni od hitrosti ohlajanja kakor tudi od anizotropije njunih lastnosti (površinske energije...) ter mehanizmov in kinetike rasti. Pri manjših ohlajevalnih hitrostih je na morfologijo karbidov izrazito vplivala anizotropija površinske energije. Zato so bili delci oktaedrične oblike kot tudi močno razvejeni dendriti MC-karbida pretežno obdani s habitusnimi ravninami {I II}. Pri večjih hitrostih ohlajanjaso nastali skeletni karbidi s številnimi vejami v smereh <O O 1>, ki so se pogosto razvejile. V ternarnem evtektiku (y + MC + M,B,) je imel MC-karbid obliko tankih ploščic. Borid M3B2 je bil navzoč v okviru ternarnega evtektika. Kristaliti borida so bili sestavljeni iz vzporednih lamel, ki so se pogosto razvejile. Pri povečani hitrosti ohlajanja je postala njihova oblika bolj nepravilna. In this work we studied the morphology of the MC carbide and the M3B2 boride in the Ni-based superalloy GMR 235 in the as-cast condition. Normally and deep-etched metallographic specimens, as well as electrolitically extracted carbides and bori des were investigated, mainly in a scanning electron microscope. Since primary crystallisation of the y phase took place on solidification, boride and carbide phases were present predominantly in the interdendritic region. Their size and morphology were dependent on the coolingrate, their anisotropic properties (e. g. surface energy), as well as on their growth mechanisms and kinetics. At lower cooling rates, the carbide morphology was strongly influenced by the anisotropy of the surface energy. Therefore, the octahedral particles and the strongly branched MC dendrites were predominantly bound with {I II} habitus plan es. At higher cooling rates, a skeletal morphology prevailed. In the ternary (y + MC + M,B,) eutecticthe MC carbide had a platelike morphology. The M3B2 boride was only present in the ternary eutectic. Boride crystallites consisted of parallel plates, which branched frequently. At higher cooling rates the boride shape became more irregular. nikljeva superzlitina morfologija karbidi boridi GMR 235 Ni-based superalloy morphology carbides borides GMR 235 true false true Slovenski jezik Angleški jezik Znanstveno delo 2012-06-01 12:59:01 2012-06-01 12:59:02 2022-04-15 13:45:36 2021-04-11 03:28:02 2002 0 0 str. 361-365 št. 6 Letn. 36 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1580-2949 669.245:620.18 106193664 267946 1580-2949 URN:SI:UM:DK:9VLWU9ZP Materiali_in_tehnologije_2002_Zupanic_Morfologija_karbida_MC_in_borida_M3B2_v_liti_Ni-superzlitini_GMR_235.pdf Materiali_in_tehnologije_2002_Zupanic_Morfologija_karbida_MC_in_borida_M3B2_v_liti_Ni-superzlitini_GMR_235.pdf 1 0898F09CF80D24145770B334EC21DC2F d253b206a053f9bb9c2b6e6ff6bb2c9440ccf14cbdbd638bfc63cbec69c63c7b ff5a35ea-7c0d-11eb-bb7a-00155d0001ca 20.500.12556/dkum/17d2fa8c-46d4-48c6-a878-7e8370ee47f7 https://dk.um.si/Dokument.php?lang=slv&id=109936 http://mit.imt.si/Revija/izvodi/mit026/zupanic.pdf 1 https://dk.um.si/Dokument.php?lang=slv&id=109935 Fakulteta za strojništvo 0 0 0