Superior ECM Performance of α + β Titanium Alloy TC11 for Narrow Blisk Channels

Electrochemical machining (ECM) offers a novel solution for forming and manufacturing aero-engine narrow-channel blisks from difficult-to-machine titanium alloys due to its non-contact processing method. This study investigates the electrochemical dissolution and machining characteristics of α + β titanium alloy TC11, using TC4 and TC6 for comparison in 10% NaCl solution. Potentiodynamic polarization tests revealed TC11 had the highest decomposition voltage (>7 V). Electrochemical impedance and XPS analyses confirmed a dual-layer passivation film structure on all alloys, with TC11 exhibiting significantly higher film resistance, indicating superior corrosion resistance. In pulse ECM of narrow blade channels, TC11 demonstrated the best machining accuracy, yielding the smallest channel width (3.68 mm), taper (0.59 mm) and taper angle 4.59°, alongside the lowest surface roughness (3.973–5.186 μm). This is attributed to its highly stable passivation film, which minimizes stray corrosion. The results establish TC11 as a promising material for high-precision electrochemical machining applications.