Low Temperature Physics: 37, 609 (2011); https://doi.org/10.1063/1.3645014 (9 pages)
Strain hardening and microstructure evolution during uniaxial compression of ultrafine grained zirconium in temperature range 4.2-300 K
A.V. Podolskiy1,3, S.N. Smirnov1, E.D. Tabachnikova1, V.Z. Bengus1, A.N. Velikodny2, M.A. Tikhonovsky2, B. Bonarski3, C. Mangler3, and M.J. Zehetbauer3
1B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
2National Science Center "Kharkov Institute of Physics and Technology" 1 Academicheskaya St., Kharkov 61108, Ukraine
3Physics of Nanostructured Materials, Faculty of Physics, University of Vienna Boltzmanngasse 5, Wien A-1090, Austria
Received November 2, 2010
Mechanical properties of ultrafine-grained (UFG) zirconium (grain size 200 nm), produced by a combination of extrusion, wire drawing and annealing, were studied at temperatures 4.2 – 300 K in uniaxial compression and compared with coarse grained (CG) Zr. The texture and microstructure evolution with increasing strain was examined by using X-ray diffraction and transmission electron microscopy were carried out. Volume fractions of twins have been determined for UFG and CG Zr. It is been found that the activity of twinning is lower in UFG Zr in comparison with CG Zr at ambient and lower temperatures, but the contrary is true for very low temperatures (4.2 K), where twinning increases with decreasing grain sizi. The influence of internal stresses of thermal anisotropy on the processes of twinning in CG and UFG zirconium has been discussed. The effect of twinning on mechanical properties of UFG Zr has been analyzed.
PACS: 62.25.+g Mechanical properties of nanoscale materials;
Key words: zirconium, ultrafine grained metals, plasticity, twinning, strain hardening, low temperatures.