Towards electrochemical machining of powder superalloy René 88DT with high surface integrity in different solvent-based electrolytes
Han Zhao, Xiaolong Fang, Xu Han, Jun Zhang, Yefei Feng, Xu‐Qing Wang, Di Zhu
Abstract
• The surface quality is less sensitive to current density in NaCl-glycol than in NaNO 3 -aqueous solutions, maintaining a high level regardless of the current density. • During electrochemical machining in NaCl-glycol solutions, no insoluble electrolytic products are formed, and no oxides are generated on the anodic surface. • The tensile properties of René 88DT after electrochemical machining in NaCl-glycol solutions are comparable to those of René 88DT after grinding, at both room and elevated temperatures. Electrochemical machining (ECM) presents numerous applications in the production of aero-engine components. The effects of current density on surface quality during ECM of René 88DT in NaCl-ethylene glycol and NaNO 3 -aqueous solutions was investigated here. The results indicated that the René 88DT surface has lower sensitivity to current density and more homogeneous electrochemical dissolution in NaCl-glycol solution than in NaNO 3 -aqueous solution, which results in the suppression of stray corrosion and consistently high surface quality regardless of current density. These strengths are attributed that C 2 H 5 O 2 - and Cl - ions replace OH – ions and combine with alloy ions to form solubles and complexes, which prevent the formation of obstructive passive film, oxide layer, and insoluble electrolytic products. The electrochemical dissolution model in two solutions was established. Furthermore, the high tensile strength and precision machinability of René 88DT in NaCl-glycol solution were also demonstrated.