Optical strain measurement through digital image correlation during tensile testing was utilised to study the effect of strain rate and welding defects on localisation of plastic deformation in friction stir welded and electron beam welded phosphorous-alloyed oxygen-free copper. Welds cut from full-size nuclear waste copper canisters and additionally made defective welds were studied. Optical strain measurement represents a new way of studying deformation of materials and obtaining local material data. The data was used to construct strain maps and estimate local true stress–strain curves. Using Gini coefficients to quantify strain localisation, it appears that the lower strain rate resulted in slightly faster localisation of plastic deformation with lower stress level.
RosborgB. and WermeL.: ‘The Swedish nuclear waste program and the long-term corrosion behaviour of copper’, J. Nucl. Mater., 2008, 37, 142–153. doi: 10.1016/j.jnucmat.2008.06.025
2.
ShoesmithD. W.: ‘Assessing the corrosion performance of high-level nuclear waste containers’, Corrosion, 2006, 62, 703–722. doi: 10.5006/1.3278296
3.
CederqvistL.: ‘FSW to Seal 50 mm thick copper canisters – a weld that lasts for 100,000 years’, Proc. 5th Int. Friction Stir Welding Conf., Metz, France, September 2004.
4.
SavolainenK., SaukkonenT. and HänninenH.: ‘Localization of plastic deformation in copper canisters for spent nuclear fuel’, World J. Nucl. Sci. Technol., 2012, 2, 16–22. doi: 10.4236/wjnst.2012.21003
5.
KouS.: ‘Welding metallurgy’, 2nd edn, 2003, New York, John Wiley and Sons.
6.
SavolainenK.: ‘Friction stir welding of copper and microstructure and properties of the welds’, PhD Thesis, Aalto University,
Finland, 2012.
7.
RaikoH.: ‘Canister design 2012’, Report 2012–13, Posiva Oy, Finland, 2013.
8.
GaoW., BelyakovA., MiuraH. and SakaiT.: ‘Dynamic recrystallization of copper polycrystals with different purities’, Mater. Sci. Eng. A, 1999, 265, 233–239. doi: 10.1016/S0921-5093(99)00004-0
9.
HuangS., ShuD., HuC. and ZhuS.: ‘Effect of strain rate and deformation temperature on strain hardening and softening behavior of pure copper’, Trans. Nonferrous Met. Soc. China, 2016, 26, 1044–1054. doi: 10.1016/S1003-6326(16)64201-2
10.
SuttonM. A., OrteuJ.-J. and SchreierH. W.: ‘Image correlation for shape, motion, and deformation measurements’, 2009, New York, Springer.
11.
SandströmR. and AndessonH.: ‘Creep in phosphorous alloyed copper during power-law breakdown’, J. Nucl. Mater., 2008, 372, 66–75. doi: 10.1016/j.jnucmat.2007.02.004
12.
SandströmR. and WuR.: ‘Influence of phosphorous on the creep ductility of copper’, J. Nucl. Mater., 2013, 441, 364–371. doi: 10.1016/j.jnucmat.2013.06.020
13.
KällgrenT. and SandströmR.: ‘Microstructure and temperature development in copper welded by the FSW process’, 4th Int. Symposium on Friction Stir Welding, Park City, Utah, USA, May2003.
14.
SaukkonenT., SavolainenK., MononenJ. and HänninenH.: ‘Microstructure and texture analysis of friction stir welds of copper’, Mater. Process. Texture: Ceram. Trans., 2008, 200, 53–60.
15.
SavolainenK., SaukkonenT. and HänninenH.: ‘Banding in copper friction stir weld’, Sci. Technol. Weld. Join., 2012, 17, 111–115. doi: 10.1179/1362171811Y.0000000089
16.
BossuytS.: ‘Optimized patterns for digital image correlation’, Proc. of the 2012 Annual Conf. on Experimental and Applied Mechanics, Vol. 3: Imaging methods for novel materials and challenging applications, 2013.
GiniC.: ‘Variabilitá e Mutabilita’, 1912. Reprinted in Memorie di Metodologia Statistica (Eds. E. Pizetti and T. Salvemini.) Rome, Libreria Eredi Virgilio Veschi, 1955.
19.
TaniguchiN. and KawasakiM.: ‘Influence of sulphide concentration on the corrosion behaviour of pure copper in synthetic seawater’, J. Nucl. Mater., 2008, 379, 154–161. doi: 10.1016/j.jnucmat.2008.06.010
20.
YagodzinskyyY., MalitckiiE., SaukkonenT. and HänninenH.: ‘Hydrogen-enhanced creep and cracking of oxygen-free phosphorous-doped copper’, Scr. Mater., 2012, 67, 931–934. doi: 10.1016/j.scriptamat.2012.08.018
21.
LousadaC. M., SorokaI. L., YagodzinskyyY., TarakinaN. V., TodoshcenkoO., HänninenH., KorzhavyiP. A. and JonssonM.: ‘Gamma radiation induces hydrogen absorption by copper in water’, Sci. Rep., 2016, 6, 24234. doi: 10.1038/srep24234
