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<p>Silicon carbide particle-reinforced aluminum matrix (SiC<sub>P</sub>/Al) composites are widely used in aerospace and microelectronics due to their high strength, thermal conductivity, and wear resistance. However, the presence of hard and brittle SiC particles makes them extremely difficult to machine, especially at medium to high volume fractions. To address this challenge, electrochemical mill-grinding (ECMG)—a hybrid process integrating electrochemical milling and mechanical grinding using an abrasive tool electrode—was employed for the efficient machining of 45 vol% SiC<sub>P</sub>/Al composites. In this study, the potentiodynamic polarization curve of 45 vol% SiC<sub>P</sub>/Al composites in 20wt% NaCl solution was clarified into five stages, and the transpassive voltage was identified as 1.34&#xa0;V, providing a reference for machining voltage selection in ECMG. Comparative analysis of surface morphologies and EDX results revealed that aluminum at feed mark protrusions is preferentially dissolved by electrochemical effect, while SiC particles are removed primarily via detachment. This selective dissolution flattens the grinding-induced feed mark protrusions, significantly reducing surface roughness. Further analysis showed that mechanical grinding effect dominates in the tool electrode front area (Area P). In contrast, the rear area (Area Q) is primarily governed by electrochemical effect, which determines both the material removal mechanism and the resulting surface morphology. Therefore, the depth of the rear area Q is approximately 20&#xa0;μm greater than that of the front area P. This distinction in removal mechanisms leads to differing feed mark orientations: the surface by ECMG exhibits forward feed marks, whereas the surface by mechanical grinding exhibits backward feed marks. Parameter experiments showed that higher voltages enhanced electrochemical effect, promoting the dissolution of grinding-induced protrusions and thereby reducing surface roughness. A minimum surface roughness of Ra 1.15&#xa0;μm was achieved at a machining voltage of 9&#xa0;V and a depth of 100&#xa0;μm.</p>

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Surface roughness reduction via preferential dissolution of feed mark protrusions in electrochemical mill-grinding of SiCP/Al composites

  • 期刊论文

  • 发表日期：

    2025年12月2日

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  • Yuehong Ma,
  • Xiaolong Fang,
  • Qingqing Yu,
  • Ningsong Qu

摘要

Silicon carbide particle-reinforced aluminum matrix (SiCP/Al) composites are widely used in aerospace and microelectronics due to their high strength, thermal conductivity, and wear resistance. However, the presence of hard and brittle SiC particles makes them extremely difficult to machine, especially at medium to high volume fractions. To address this challenge, electrochemical mill-grinding (ECMG)—a hybrid process integrating electrochemical milling and mechanical grinding using an abrasive tool electrode—was employed for the efficient machining of 45 vol% SiCP/Al composites. In this study, the potentiodynamic polarization curve of 45 vol% SiCP/Al composites in 20wt% NaCl solution was clarified into five stages, and the transpassive voltage was identified as 1.34 V, providing a reference for machining voltage selection in ECMG. Comparative analysis of surface morphologies and EDX results revealed that aluminum at feed mark protrusions is preferentially dissolved by electrochemical effect, while SiC particles are removed primarily via detachment. This selective dissolution flattens the grinding-induced feed mark protrusions, significantly reducing surface roughness. Further analysis showed that mechanical grinding effect dominates in the tool electrode front area (Area P). In contrast, the rear area (Area Q) is primarily governed by electrochemical effect, which determines both the material removal mechanism and the resulting surface morphology. Therefore, the depth of the rear area Q is approximately 20 μm greater than that of the front area P. This distinction in removal mechanisms leads to differing feed mark orientations: the surface by ECMG exhibits forward feed marks, whereas the surface by mechanical grinding exhibits backward feed marks. Parameter experiments showed that higher voltages enhanced electrochemical effect, promoting the dissolution of grinding-induced protrusions and thereby reducing surface roughness. A minimum surface roughness of Ra 1.15 μm was achieved at a machining voltage of 9 V and a depth of 100 μm.