Experimental Study on the ECM and PECM of Pressed and Casted γ-TiAl Alloys for Aero Engine Applications

Abstract

Based on low density and excellent high-temperature performance, Gamma Titanium Aluminide (γ-TiAl) is adequate for high temperature structural material in aero engine components, such as turbine blades, compressor casings etc. However, due to low temperature ductility and fracture toughness, problems occur by machining these alloys with traditional cutting techniques. Electrochemical machining (ECM) is a reasonable alternative because of its specific process characteristics. Therefore, this paper focuses on the experimental research of electrochemical removal behaviour of typical new materials in aero engine applications. The theoretical calculation was used to compare and analyze the test results. Furthermore, experiments with precise ECM with vibration (PECM) were performed to improve surface roughness. From the results of the examined pressed and casted γ-TiAl alloys, having almost the same chemical composition, it is concluded that the more homogeneous the phase, the higher is the reachable material dissolving rate (va) and less energy is needed in order to get a same value of va. The cross-sections attest that the electrochemical process has no influence on the rim zone.