Wire electrochemical micromachining of nitinol shape memory alloy using different electrolytes

Nitinol shape memory alloy (SMA) is one of the toughest and difficult to cut advanced smart material. Also, the properties of the material should not be affected during machining operations. Wire electrochemical machining (WECM) was created to address these issues as a result of technological innovation and the necessity for high aspect ratio products. This paper explains the effect of different aqueous solution of electrolytes, i.e., NaBr, NaCl, and NaNO3 on nitinol dimensional and surface characteristics by microgroove fabrications during WECM. Further, in order to improve machining performance, the machining has been carried out with mixed and ozonated mixed conditions of NaCl + NaNO3 electrolytes, and the quality of machined microgrooves is examined for surface topography, dimensional precision, and homogeneity. The best electrolyte, i.e., NaCl + NaNO3 has been further used in combination with EDTA (ethylenedinitrilotetraacetic acid disodium salt dehydrate) complexing agent under non-ozonated and ozonated conditions and resulted in improved surface finish and dimensional features of the microfeatures by expeditiously removing sludge and dissolved products and increasing the efficacy of dissolution than other electrolytic conditions. The average groove width of 105.86 mu m, mean depth of 264.6 mu m, average surface roughness of 0.1346 mu m, homogeneous microslit of average width of 106.40 mu m, and average surface roughness (Ra) of 0.1261 mu m have been obtained at 5 V pulse voltage and 1.4 mu m/s wire feed rate with ozonated aqueous 0.2 M NaCl + 0.2 M NaNO3 mixed with 0.2 M EDTA.