Microcosmic Mechanism of Die-sinking Mixed-gas Atomization Discharge Ablation Process on Titanium Alloy

In order to reveal the microscopic mechanism of the titanium alloy die-sinking mixed-gas atomization discharge ablation process (MA-DAP), a single-pulse-discharge test was performed using a needle electrode discharge device. According to the step-like characteristic of the single discharge waveform, the micro-erosion process could be divided into four stages: preparation for oxidation ablation; oxidation occurrence and oxide layer generation; oxidation-ablation dynamic balance and oxide layer prototype formation; oxidation-ablation termination and integral oxide layer formation. Theoretical analysis showed that the violent exothermic oxidation reaction between the oxygen medium and the high-temperature melting material introduced a large quantity of external chemical energy into the sparking region. Fast vaporization and explosion of the atomized medium after heating gave MA-DAP high particle removal power. The technological experimental results showed MA-DAP provides high material removal efficiency and strong deep-hole machining ability. The depth-to-diameter ratio of the specially shaped titanium alloy MA-DAF blind hole was 11 times that from traditional electrical discharge machining, while the cross-sectional hardness can be reduced by 45%.