Yee Ng, Xian Yi Tan, Lei Zhang, Zi Wen Tham, Hui Ru Tan, Tzee Luai Meng, Chen-Nan Sun, Zhaohong Huang, Ming Lin, Hongfei Liu,
Acoustic emission and surface modification of additively manufactured Ti-6Al-4V coupons during plasma electrolytic polishing using pulsed voltage,
Surface and Coatings Technology,
Volume 509,
2025,
132215,
ISSN 0257-8972,
https://doi.org/10.1016/j.surfcoat.2025.132215.
Abstract:
Square-pulsed voltage with a peak value of 300 V and a duty cycle of 50 % was applied for plasma electrolytic polishing (PEP) at the plasma initiation-transition stage to address the effect of pulse frequencies, ranging from 500 to 2000 Hz, on acoustic emission (AE) and surface integrity modification of additively manufactured Ti-6Al-4V coupons. In-situ measurements revealed strong correlations between the current density and AE count, not only as a function of process time t but also with the frequency variations. A transition point, ttr, has been observed. Both the current density and AE count decreased with t at t < ttr and increased at t > ttr. The ttr increased with the increase in the frequency. However, the electrolyte temperature monotonically increased with t and decreased with the increase in voltage frequency. Surface characterizations revealed effective particle removal alongside pressure wave shock-peening and integrity modifications induced by the PEP process. The effect of peening increased with the increase in the pulse frequency, which strongly correlated with the acoustic amplitudes during the PEP process. These observations, compared to those resulted from constant-voltage PEP process (working at the traditional stable stage), provide evidence for enhanced mechanical effects but weakened electrochemical reactions induced by employing the pulsed-voltage.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the A*STAR - Singapore Aerospace Programme
Grant Reference no. : M2315a0084