Isothermal precision forging of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy impeller with twisted blades

Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloy impeller is an important part in the airspace engine that serves under severe working conditions, and it requires excellent mechanical properties and high dimensional precision. However, the integral titanium alloy impeller is difficult to precisely forge because of its complex shape and poor formability. In order to develop optimum forging process of this kind of complex parts, the deformation characteristics of TC11 alloy under isothermal compressing conditions were studied. Furthermore, an alternative material, namely pure lead, was selected to model the forming process of the impeller and investigate metal flow during forging. Based on the research, local loading method was determined to forge the TC11 alloy impeller precisely under isothermal condition. The dimensional accuracy, mechanical properties and microscopic structure of the forged product satisfy operating requirements.