Modeliranje vpliva precipitacije na kinetiko statične rekristalizacije

Predalič, Matic (author), Kugler, Goran (mentor)

V diplomskem delu smo raziskovali vpliv precipitatov niobijevega karbida na proces statične rekristalizacije v avstenitnih jeklih pri različnih izbranih pogojih, kot tudi pri različnih vsebnostih niobija in ogljika. Uporabljena sta bila dva modela, ki sta bila razvita na osnovi teorije povprečnega polja. Prvi model je bil uporabljen za opis kinetike statične rekristalizacije, drugi pa za opis kinetike precipitacije NbC. Modela sta bila nato medsebojno sklopljena preko enostavnega modela za določitev mobilnosti velikokotnih kristalnih mej v odvisnosti od Zenerjevega tlaka, ki pripenja kristalne meje. Rezultati simulacij statične rekristalizacije so pokazali, da je prvi model ustrezen in daje za nabor uporabljenih parametrov pričakovane rezultate. Tudi rezultati ločenih simulacij kinetike precipitacije NbC kažejo primernost izbranega pristopa. S skloplenim modelov smo nato izvedli serijo simulacij in rezultate kvalitativno primerjali z eksperimentalnimi rezultati iz literature. Ugotovili smo, da je model zmožen opisati vse fenomene in odvisnosti, ki so bili opaženi eksperimentalno.

• Language: Slovenian
• Keywords: Preoblikovanje v vročem, statična rekristalizacija, precipitacija, poprava, deformacijsko utrjevanje, Zenerjev tlak.
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2020
• PID: 20.500.12556/RUL-120759
• COBISS.SI-ID: 31856899
• Publication date in RUL: 25.09.2020

Secondary language

• Language: English
• Title: Modelling of the influence of precipitation on the kinetic of static recrystallization

Abstract

In this thesis the influence of precipitation from Niobium Carbides on the kinetics of static recrystallization in austenitic steels was investigated for different selected conditions and amounts of niobium and carbon. Two different models based on mean field theory were applied. The first was used to describe the kinetics of static recrystallization and the second to study the precipitation kinetics of NbC. These two models were coupled by a simple model that describes the grain boundary mobility at a high angle as a function of the Zener pressure that sets the grain boundaries. The results of the static recrystallization simulations show that the first model can provide the expected results for the selected parameter set. The results of separate simulations of the precipitation kinetics of NbC also show that the approach was suitable. By using coupled models, a series of simulations were performed and the results were ualitatively compared with experimental results from the literature. It was found that our model is capable of describing all phenomena and dependencies that were observed experimentally.

• Keywords: Hot working, static recrystallization, precipitation, recovery, strain hardening, Zener pressure.