Hostname: page-component-5c6d5d7d68-wbk2r Total loading time: 0 Render date: 2024-08-19T22:21:07.920Z Has data issue: false hasContentIssue false

Microstructure Development in Copper Welded by the FSW-Process

Published online by Cambridge University Press:  01 February 2011

Therese Källgren
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
Rolf Sandström
Affiliation:
Department of Materials Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
Get access

Abstract

To ensure safe storage of nuclear fuel waste, copper canisters are proposed as corrosion barrier. One alternative for sealing the copper canisters is Friction Stir Welding (FSW). During the joining process friction heat and mechanical deformation appear between the rotating tool and the material being welded. Liquid metal will not form, since this is a solid state welding process. Three distinct microstructural zones are developed namely the nugget, the thermo-mechanically affected zone (TMAZ) and heat-affected zone (HAZ). The nugget is in the centre of the weld, where the pin is located and where severe plastic deformation occurs that leads to recrystallisation. Surrounding the nugget, the TMAZ is only partially recrystallised, due to lower temperature increase and deformation compared to the nugget. The third zone, HAZ, surrounds the TMAZ. The initial nugget can have a classic round aluminium nugget image, when the welding conditions are cold, but the steady state nugget, is wider near the shoulder and shorter in the weld root.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCE

1. Andersson, C-G., Andrews, R.E., Dance, B.G.I., Russell, M.J., Olden, E.J., Sanderson, R.M., A Comparison of copper Canister Fabrication by the Electron Beam and Friction Stir Welding, Proceedings, 2nd International Symposium on FSW, Gothenburg, Sweden, June 2000 Google Scholar
2. Werme, L., Design premises for canister for spent nuclear fuel, Swedish Nuclear Fuel and Waste management Co, SKB report TR-98–08, September 1998 Google Scholar
3. Andersson, C-G., “Development of fabrication technology for copper canisters with cast inserts, Swedish Nuclear Fuel and Waste management Co, SKB report TR-02–07, August 2001 Google Scholar
4. Murr, L.E., Liu, G., McClure, J.C., Dynamic recrystallization in friction-stir welding of aluminium alloy 1100, Journal of materials science letters 16, 18011803, 1997 Google Scholar
5. Calgrove, P., 3-d Flow and Thermal Modelling of the FSW-process, M. Sc thesis, 2001 Google Scholar
6. Russel, M.J., Development and modelling of FSW, For the degree of Doctor of Philosophy, University of Cambridge, 2000 Google Scholar
7. Metals Handbook, 10th edition, volume 2, Nonferrous Alloys and Pure metals, ASM InternationalGoogle Scholar