Analysis and research on the causes of the inability to use pure oxygen dielectric discharge ablation process on titanium alloy

Electrical discharge machining ablation (EDMA) technology is an EDM processing method that uses oxygen as the discharge medium. Compared with traditional EDM, EDMA can greatly improve the machining efficiency but is prone to combustion and explosion phenomena when machining titanium alloy and cannot obtain stable continuous processing. Therefore, this present first analyzes the oxidation characteristics of titanium alloy from the oxidation thermodynamics and kinetics of the material. Then, the structural characteristics of the oxide layer formed on the surface of the titanium alloy where combustion and explosion phenomena occur are analyzed, and the effects of the metal elements that constitute the titanium alloy on the oxide layer structure are studied to reveal the reasons for the explosions. Finally, a method of mixed-gas electrical discharge ablation processing for titanium alloy to avoid explosions is proposed. The material removal rate in the proposed approach is 10 times and 3.5 times greater than that of conventional nitrogen- and argon-assisted submersed gas-flushing EDM, respectively. This provides a new electric machining technology for the high-efficiency and sustainable processing of titanium alloy.