Near Conventional Forging of an Advanced TiAl Alloy

Abstract

Balanced mechanical properties are needed for TiAl low pressure turbine blades envisaged for use in new generation aircraft engines. However, thermomechanical processing of γ-TiAl based alloys is a challenging task due to a small “processing window”. Isothermal forging, as state of the art process for this class of material, results in high productions costs and lower productivity. Due to these facts Bohler Schmiedetechnik GmbH & Co KG has developed a higher efficient “near conventional” thermomechanical processing technology. Lower die temperature and processing at standard atmosphere as well as the use of standard hydraulic presses with higher ram speed result in a highly economical process. Subsequent heat treatment strategies can be used to tailor microstructure and, therefore, mechanical properties according to customer needs. The paper summarizes our effort to establish a near conventional forging route for the fabrication of TiAl components for aerospace industry.