Cast and Rolling Textures of NiMnGa Alloys

摘要

The texture of two polycrystalline NiMnGa magnetic shape memory alloys fabricated by directional solidification and hot rolling has been measured with high-energy synchrotron radiation and neutron diffraction. At room temperature the alloys used are composed of a modulated (7M) and non-modulated (NM) martensitic structure. The texture of the directionally solidified alloy for all phases is a pronounced fibre texture with <100> preferentially aligned along the growth direction. In the directionally solidified case a variant selection took place with [001] dominating. The texture of the hot rolled alloy shows a weak recrystallization texture with {111} and <112> aligned parallel to the rolling plane and rolling direction, respectively. The texture results are discussed with respect to material, processing and phase transformations including variant selection.