Portal de Periódicos da CAPES

Compression-induced texture change in NiMnGa-polymer composites observed by synchrotron radiation

2007; American Institute of Physics; Volume: 101; Issue: 9 Linguagem: Inglês

10.1063/1.2670414

1520-8850

N. Scheerbaum, Dietrich Hinz, Oliver Gutfleisch, Werner Skrotzki, L. Schultz,

Shape Memory Alloy Transformations

Composites consisting of magnetic shape memory (MSM) particles embedded in a polyester matrix were prepared. Single-crystalline MSM particles were obtained by mortar grinding of melt-extracted and subsequently annealed Ni50.9Mn27.1Ga22.0 (at. %) fibers. The crystal structure of the martensite is tetragonal (5M) with c<a=b. Magnetic characterization of these composites shows indirect evidence for stress induced twin boundary motion in the MSM particles, as the compressed composite is easy to magnetize in the direction of compression and more difficult to magnetize in the perpendicular directions. The texture of all the embedded MSM particles is investigated before and after compression by means of synchrotron radiation. In the initial state, the MSM particles in the composite have a random texture, i.e., there is no preferred orientation of the c axis. After a 30% compression (height reduction), the MSM particles have a (004)-fiber texture in the direction of compression. This is unambiguous evidence for stress induced twin boundary motion within the MSM particles.