In Situ Characterization of the Elasticity and Stress-Induced Phase Transformation of NiTi Shape-Memory Alloy |
| T. Grabeca, K. Zoubkováb, P. Stoklasovác, M. Ševčíkc, P. Sedlákc, M. Janovskác, H. Seinerc, M. Landac
aNuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 250 68 Řež, Czech Republic bFaculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Trojanova 13, 120 00 Prague 2, Czech Republic cInstitute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejškova 5, 182 00 Prague 8, Czech Republic |
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| In the presented paper, a sample of polycrystalline shape-memory NiTi alloy is studied under compression up to 5% by the means of laser-excited and laser-detected ultrasound waves. The evolution of a propagation velocity of the surface acoustic wave is measured in situ during mechanical loading. An inverse method based on the Ritz-Rayleigh numerical approach is then used to obtain the development of elastic properties of the sample. This process enables an analysis of the evolution of stress-induced transformation from the austenitic to the martensitic phase with the possibility to describe several stages of such transformation, i.e., the transformation to full R-phase, its reorientation causing strong anisotropy of the polycrystalline sample, and consecutive gradual transition to martensite. |
DOI:10.12693/APhysPolA.134.811 PACS numbers: 43.20.+g, 81.05.Bx, 62.20.fg |