Regensburg 2013 – scientific programme
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MI: Fachverband Mikrosonden
MI 9: Poster: Microanalysis and Microscopy
MI 9.5: Poster
Wednesday, March 13, 2013, 15:00–17:00, Poster B2
Investigations of Co-Ni-Al ferromagnetic shape memory alloys by means of X-ray Kossel diffraction and the EBSD method — Enrico Langer1, Siegfried Däbritz1, •Mateus Melo1,2, Leonid Potapov1,3, and Jaromir Kopeček4 — 1Technische Universität Dresden, Institut für Festkörperphysik, Helmholtzstraße 10, 01062 Dresden, Germany — 2Universidade Presbiteriana Mackenzie, Departamento de Engenharia de Materiais, Rua da Consolação, 930, CEP: 01302907, Consolação - São Paulo - SP, Brazil — 3St. Benno-Gymnasium Dresden, Pillnitzer Straße 39, 01069 Dresden, Germany — 4Academy of Sciences of the Czech Republic, Institute of Physics, Na Slovance 2, 18221 Prague, Czech Republic
Current research activities are focussing on a complete understanding of the structure and the behavior of ferromagnetic shape memory alloys (FSMA). The Co-Ni-Al system attracts special attention in the area of FSMA due to certain features such as good oxidation resistance, low density and appreciable ductility at room temperature. The present work studied austenitic single crystals with nominal composition Co38Ni33Al29 (matrix B2-β-phase with precipitates of A1-γ-phase) by means of X-ray Kossel diffraction and EBSD within a scanning electron microscope. The samples were prepared by the Bridgman method and grown in [100] direction. Overlaps of Kossel reflections of two different crystal phases were observed which allowed to determine precisely the orientation relationship as Kurdjumow-Sachs: (111)A1 || (110)B2, [110]A1 || [111]B2. Moreover, remarkable dark regions (lower backscatter coefficient η) between the B2 matrix and the γ-phase were seen using backscattered electrons. On the basis of the Kossel investigations it may be concluded that this structure along the boundary is connected to the measured exact plane orientation relationship (misorientation within a few tenths of a degree) and therefore reveals areas of excellent crystal quality with very low dislocation density.