| In Situ Texture Measurements of Stress-Induced Martensite in Superelastic NiTi using Hard Synchrotron Radiation | ||
| Mr. Mahamudul Hasan1, Prof. Wolfgang Schmahl2, Dr. Alberto Baruj3, Dr. Jafar Khalil-Allafi4 and S. Gollerthan5, 1Fakultät für Geowissenschaften / department of Earth Sciences, Materials Research, Ruhr -University Bochum / Ludwig-Maximilians-Universität, Universitätsstraße 150, Bochum, 44780, Germany, 2department of Earth Sciences, Materials Research, Ludwig-Maximilians-Universität, Theresienstr. 41, München, 80333, Germany, 3Materials Science, Comision Nacional de Energia Atomica, Buenos Aires, Argentina, 4Faculty of Materials Engineering, Sahand University of Technology, Tabriz, 51335-1996, Iran, 5Materials Science, Ruhr-Universität Bochum, D-44780, Bochum, 44780, Germany
We investigated the local textural evolution in a superelastic Ni50.7Ti49.3 alloy under applied stress using high-energy synchrotron x-ray diffraction in transmission geometry. Texture information is identified from the intensity variations along Debye-Scherrer rings recorded on area detector diffraction images. The original texture of the cold rolled B2 austenite and that of the stress-induced B19' martensite are quantitatively related to the features of the superelastic plateau in the stress-strain curve. The {110}A austenite plane normals are aligned in the rolling direction and {100}A is in the transverse direction. Due to the B2-B19' lattice correspondence the {110}A peak splits into four martensite peaks {020}M, {-111}M, {002}M and {111}M . The stress-induced martensite is strongly textured from twin variant selection in the stress field with {020}M aligned in the loading direction while the {002}M and {111}M maxima are at 70º and 60º from the loading direction. (B19´ unit cell setting: a = 2.87Å, b = 4.59Å, c = 4.1Å, γ= 96.2º).
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