New experimental information on the effect of Ni, Cu and Mn on the nitride precipitation temperature and the phase relations in the Fe-Cr-N system is presented. The samples were heat treated under flow of pure and mixed nitrogen gas at different temperatures. The microstructure was investigated by SEM and the nitrogen composition by LECO nitrogen analyzer. The phase equilibria between austenite and Cr2N nitride have been studied at 1173 K and 1373 K using the sealed capsule technique to measure the N activity and SEM-EDS to measure the chemical compositions of the individual phases followed by analysis using LECO nitrogen analyzer. Deviations from theoretical calculations which have been done by Thermo-Calc using the TCFE7 database were observed. E. g. Thermo-Calc predicted single phase austenite at higher Cr content in contrast to experiments which showed austenite and Cr2N nitride phases. Furthermore, the experimental data show slight changes on the extension of the single phase austenite field whereas the calculations show larger effects by addition of Ni, Cu and Mn.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-118092 |
| Date | January 2012 |
| Creators | Khoda Karami, Mina, Kohanzadehmaranlou, Ali |
| Publisher | KTH, Materialvetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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