| ZHENG Yafeng,WANG Hechao,HUANG Tiantian,MA Yongbo,TIAN Yi,WANG Ye,WU Guolong,YAO Jianhua.Material Removal Mechanisms during Laser-assisted Jet Electrochemical Processing of WC-Ni Cermet[J],54(11):130-143 |
| Material Removal Mechanisms during Laser-assisted Jet Electrochemical Processing of WC-Ni Cermet |
| Received:December 04, 2024 Revised:March 14, 2025 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.11.011 |
| KeyWord:cermet material removal processing laser-assisted jet electrochemical machining passivation layer removal mechanisms |
| Author | Institution |
| ZHENG Yafeng |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| WANG Hechao |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| HUANG Tiantian |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| MA Yongbo |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| TIAN Yi |
China Academy of Engineering Physics, Sichuan Mianyang , China |
| WANG Ye |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| WU Guolong |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
| YAO Jianhua |
Institute of Laser Advanced Manufacturing,College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China;Collaborative Innovation Center of High-End Laser Manufacturing Equipment Co-Sponsored by Ministry and Province, Hangzhou , China |
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| Abstract: |
| In response to the challenges posed by multi-phase dissolution inhomogeneity, passivation, and stray corrosion during the electrochemical machining of cermet materials, the work aims to conduct a comprehensive comparative experimental study on WC-Ni cermet under neutral electrolyte conditions. Jet Electrochemical Machining (JECM) and Laser-Assisted Jet Electrochemical Machining (LAJECM) were employed to elucidate the material removal mechanisms. The first phase of the study involved electrochemical testing of WC-Ni cermet to investigate their dissolution and passivation behavior in a neutral NaCl electrolyte. Subsequently, the Ni and WC phases dissolution, passivation, and removal mechanisms during the LAJECM process were explored. This was achieved through a series of comparative experiments involving Single-Jet Electrochemical Machining and Laser-Assisted Jet Electrochemical Machining on WC-Ni cermet. The analysis was further enhanced by investigating material removal mechanisms through electrochemical testing, laser confocal microscopy (Vk-X1000), oscilloscope and current probe (Tektronix TDS 2012C), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS) to provide a comprehensive insight into the underlying processes. Electrochemical test results indicated that WC-Ni cermet underwent three distinct stages during electrochemical machining, including dissolution, passivation, and over-passivation. In the single electrochemical machining, the machined surface exhibited intermediate bumps, with the cross-sectional profile resembling a 'W' shape, and the passivation layer displayed an uneven surface characterized by stacked bumps. However, under simultaneous laser irradiation, the cross-sectional profile shifted to an approximate 'U' shape, the passivation layer became smoother, and aggregated particles were observed in the distribution. Furthermore, the laser enhanced processing depth, suppressed stray corrosion at the edges of the pits, and improved the precision of the process. Energy Dispersive Spectroscopy (EDS) analysis revealed that the tungsten (W) in the passivation layer primarily existed as tungsten trioxide (WO3) during the single electrochemical machining. In contrast, during the laser-assisted jet electrochemical machining, the oxygen content in the surface passivation layer decreased, while the tungsten and carbon contents increased. In the LAJECM process, the synergistic effect of laser and electrolyte promotes the homogeneous dissolution of materials. The thermal effect under laser action prompts a sharp increase in the electrolyte temperature, which in turn accelerates the movement of ions in the solution and enhances the conductivity of the electrolyte. The laser-induced impact force effect leads to a cathodic shift in the anodic equilibrium potential, which increases the processing current density under the condition of constant external voltage. The laser irradiation makes the temperature difference between the laser irradiated area and the non-irradiated area increase, and the resulting micro stirring effect promotes the material transfer. The increase in local temperature under laser action leads to evaporation of water and increase in salt concentration, which further accelerates the material dissolution. In terms of electrochemical action, the electrolyte penetrates the substrate through the cracks on the passivation layer, weakening the bonding force between the surface passivation layer and the substrate, leading to the start of dislodging of the passivation layer and WC particles under the impact of the electrolyte. During the intervals between the laser pulses, electrochemical reactions re-dominate the surface processes, leading to the formation of a new passivation layer. This dynamic equilibrium of the formation of the laser-assisted jet electrochemical machining of the material removal mode in the processing area shows the passivation layer destruction and regeneration alternately, achieving the continuous removal of the material. |
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