This thesis investigated the microstructure and mechanical property of RRR( high
purity) and RG (low purity) niobium (Nb) sheet material. RRR Nb is used in the
fabrication RF cavities. Our method involves processing bulk niobium by equal channel
angular extrusion (ECAE) and then cross rolling to obtain sheets. This work is a study of
the effect different thermomechanical processing variables have on the microstructure
niobium sheets.
Recrystallization behaviors strongly depended on the purity levels. Tensile tests
on sheets clearly indicated the anisotropy in the sheet material. The ductility of the sheet
was found to be the largest at an angle of 45o to the rolling direction. There was no
apparent relationship observed in the yielding behavior in the different samples. The
formability of the sheet measured by the anisotropy ratio suggested a strong dependence
of anisotropy on texture. Texture results obtained show that different routes of ECAE can
lead to variety of textures in final sheet material.
Correlations between the microstructure and the ECAE routes suggest that
effective control of microstructure is possible by the thermomechanical steps followed in
this study.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2347 |
| Date | 15 May 2009 |
| Creators | Balachandran, Shreyas |
| Contributors | Griffin, Richard B |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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