Open Access
Article Number 02009
Number of page(s) 6
Section Principles, Simulations, Materials: Background
Published online 01 September 2009
ESOMAT 2009, 02009 (2009)
DOI: 10.1051/esomat/200902009

Effect of aging and solution annealing on transformation and deformation mechanism of super-elastic Ni50.9%-Ti alloy in nano- scale

A. Ghabchi1, 2, 3, J. Khalil-Allafi1, X.W. Liu4, O. Söderberg4, E. Turunen2 and S-P Hannula4

1  Sahand University of Technology, Department of Materials Engineering, Tabriz, Iran
2  Technical Research Center of Finland (VTT), Espoo, Finland
3  Center for Thermal Spray Research, Material Science and Engineering Department, SUNY, Stony Brook, USA
4  Department of Materials Science and Engineering, Helsinki University of Technology, Espoo, Finland

Published online: 1 September 2009

Effects of aging and solution annealing treatment on the super elastic respond of the cold-worked Ni50.9%-Ti thin wire was studied in nano-scale utilizing instrumented nanoindentation. The nanoindentation results were coupled with the tensile test results to provide better insight to the governing deformation mechanisms. The first applied heat treatment consisted of solution annealing treatment (850°C for 60 minutes) followed by aging at 450°C for 30 minutes and as second heat treatment the cold-worked wire was aged at 450°C for 30 minutes with no prior solution annealing treatment. Both tensile test and nanoindentation results showed better super elastic behavior for the wire subjected to second treatment. Indentation displacement bursts were observed in loading course after both treatments. However, slope changes in unloading course of indents were recorded after second heat treatment which might be due to reverse phase transformation. Surface asperities on the post-indented surface after first treatment were observed far away from indentation stress field by atomic force microscopy.

© Owned by the authors, published by EDP Sciences 2009