Study of Residual Stress in Nickel Micro Parts Made by Electrochemical Additive Manufacturing

Electrochemical additive manufacturing (ECAM) is a novel process which uses localized electrochemical deposition as the material addition mechanism for additive manufacturing (AM) of metal parts at room temperature. While ECAM possesses highly controllable process parameters, complex electrochemical phenomena, such as nucleation patterns and hydrogen codeposition, may cause residual stresses in the output parts. To better predict this behavior for increased reliability and future commercial adoption of ECAM, localized deposits were studied under several controlled combinations of electrochemical process parameters under both constant-time and constant-height termination criteria. The residual stress was then measured using an atomic force microscopy (AFM) indentation procedure. Significant trends that were found include increased stress magnitude with increasing applied voltage, and the higher influence of voltage and then pulse period on the resulting stress, compared to the duty cycle. It was also seen that shorter deposition times led to compressive stresses and longer times led to tensile stresses.