20.500.12556/RUL-111489 Razvoj mikrostrukture v deformirani nikljevi zlitini 625 Microstructure development in deformed nickel alloy 625 Glavni cilj doktorske disertacije je raziskava vpliva deformacije in toplotne obdelave na izločanje sekundarnih faz nikljeve zlitine 625 z različno kemijsko sestavo. V vroče deformiranih ploščah, ki imajo pozitivne segregacije z niobijem smo opazovali izločanje sekundarnih faz po staranju na temperaturi 750 °C. Ker se je povprečni delež niobija spreminjal čez segregacijski pas, smo spremljali izločanje sekundarnih faz pri različnem povprečnem deležu niobija. Pri majhnem povprečnem deležu niobija (< 4 mas.% Nb) so deformirana zrna omogočala izločanje večjega števila izločkov ?'' (Ni3Nb). Nasprotno, v rekristaliziranih zrnih je bila gostota izločkov ?''-faze veliko manjša, izločali pa so se samo na dvojčkih in drsnih linijah. Z večjim delež niobija (> 4 mas.% Nb) je izločanje večjega števila finih izločkov ?'' potekalo v deformiranih in rekristaliziranih zrnih. Na deformacijskem dilatometru smo spreminjali temperaturo deformacije in jo povezali z izločanjem ?''-faze s pomočjo EBSD-analiz. Temperatura deformacije (950, 1050 in 1150 °C) ima vpliv na porazdelitev faze ?'' in je povezana z lokalno razliko v orientaciji. V zadnjem delu disertacije smo raziskovali vpliv žarjenih in deformiranih vzorcev na utrjevanje z izločanjem ?'' v homogeniziranih ploščah z različnim dodatkom titana in aluminija. Na osnovi meritev trdot in mikrostrukturnih preiskav, ima dodatek titana (0,36 mas.%) in aluminija (0,35 mas.%) majhen vpliv na izločanje ?'' faze. Trdota deformiranih vzorcev se je po staranju na temperaturah 700 in 750 °C zaradi izločanja ?'', bolj povečala v primerjavi z žarjenimi vzorci. Majhno povečanje v natezni trdnosti pa je bilo povezano z deležem niobija (~ 3,3 mas%). The main objective of doctoral thesis was to research the influence of the deformation and heat treatment on the precipitation of secondary phases in chemically modified Inconel 625. The precipitation of secondary phases during aging at 750°C was researched in hot rolled plates containing positive segregations with niobium. Due to segregations the fraction of niobium changed acros the segregation band. The deformed grains enabled precipitation of large number of fine ?'' (Ni3Nb) precipitates when fraction of niobium was low (< 4 wt.%). The opposite was observed in recrystalized grains where only a small number of ?'' precipitates was observed on twins and glide planes. The precipitation of large number of fine precipitates ?'' takes place in deformed as well as recrystallized grains when niobium content was high (> 4 wt.%). The precipitation of ?'' in samples hot compressed at different temperature was researched with EBSD-analyis. The local change in orientation of hot-deformed samples at different temperature (950, 1050 in 1150°C) had influence on the distribution of the ?''-phase. In the last part the influence of deformed and annealed samples was researched, on precipitation hardening by ?'' in homogenized plates with different addition of titanium and aluminium. The increased content of aluminium (0,36 wt.%) and titanium (0,35 wt. %) had small influence on the precipitation of the ?''. The hardness of deformed plates after aging at 700 and 750°C increased more than in annealed plates. Small increase in tensile strength was conected with low content of niobium (~ 3,3 wt.%). Inconel 625 segregacije vroča deformacija modifikacija s Ti in Al staranje Inconel 625 segregation hot deformation modification with Ti in Al aging true false false Slovenski jezik Angleški jezik Doktorsko delo/naloga 2019-10-02 07:45:05 2019-10-02 07:45:12 2022-08-23 03:43:23 0000-00-00 00:00:00 2019 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 71301 1844063 4380.pdf 4380.pdf 1 AC55BB5CD3CEFF45CEA52F4A41294F74 b872ecd0c82111b320284dc64cab86fb6c362669a9d3a5d34c03b1b019c2f5b6 66da150d-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=123354 4383.pdf 4383.pdf 1 EE9F898BB48E787885D75C2267498C2F 430258732f8a14d8096ea532905ace3f23cf257048fd741b2d84ff341a0cddd5 6723f7df-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=123358 4382.pdf 4382.pdf 1 0A52548BE7BB89697CD6A6A2D720F071 5c15e393d99b131ef94549ade028f4c9273874f1e17e184e5bd890a2c52ecfa0 6710e7f9-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=123357 4384.pdf 4384.pdf 1 4BA6128EA2C6EB9017C8779B1BE83914 3219d061dbfc61dee94b05b99efe0f2fc9eaa4d0e0c9b7f7fbacf41fd85d6513 6742fda4-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=123360 4381.pdf 4381.pdf 1 3937C7D43AFD17546F1D33956D347854 a053adab6117db3ec6551e2d170e8f97f1d2bafdc1d657c1a732d4a0093394a9 66fdd1b2-a1b7-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=123356 Naravoslovnotehniška fakulteta 0 0 0