Machining characteristics of submersed gas-flushing electrical discharge machining of Ti6A14V alloy

摘要

To investigate the discharge machining characteristics of a type of Ti6Al4V alloy in air and argon working media, the workpieces were submerged in water to perform submersed gas-flushing electrical discharge machining. A single-pulse discharge study found that the Ti6Al4V alloy can react with oxygen and nitrogen in the air medium during discharge to generate high-resistance and high-melting-point substances, which lead to a step-like rise in the discharge machining voltage. In the argon medium, no chemical reaction occurs between the Ti6Al4V alloy and the argon medium; thus, the discharge machining voltage is horizontal, and the discharge crater is larger than the air medium. The experiment result shows that the machining efficiency in the argon medium is greater than three times that in the air medium. Almost no microcracks and micropores are observed on the surface of the Ti6Al4V alloy, the recast layer has a uniform thickness and thin, and no longitudinal microcracks are observed. However, the relative electrode wear ratio is higher than that in the air medium because it loses the coating protection effect of the etching product. This experimental method has found an effective processing technique for improving the machining efficiency and surface integrity of the Ti6Al4V alloy.