Investigations on the surface texture after pulsed electrochemical machining (PECM) of the magnetic shape memory alloy NiMnGa

Materials such as shape memory alloys enable novel approaches to solutions, that numerous companies are pioneering their industrial use. A reversible solidstate transformation allows components to apply a directed tension induced by e.g. temperature, magnetic field or pressure. However, various studies show that conventional mechanical processing causes undesirable changes in the motion capability. Precise electrochemical machining is an alternative production technology that allows functional properties to be preserved. The study is dedicated to NiMnGa, which can elongate up to 6 % under the impact of a magnetic field. First, electrochemical material characterization is performed in accordance to DIN SPEC 91399. In further experiments the surface texture is studied by confocal and SEM microscopy. The results provide knowledge about the influence of PECM on the components surface that is produced by side gap machining by variation of feedrate and voltage.