Wire-arc additive manufacturing of pre-forms for forging of a Ti-6Al-4V turbine blade

Abstract

The production of Ti-6Al-4V components is of great importance for many fields, especially the aerospace industry. High-performance parts made of Ti-6Al-4V are traditionally produced by hot forging and require expensive dies. Besides, to obtain net shape parts, extensive machining operations are used which may entail a material yield of less than 10 %. For many applications, net-shape technologies such as additive manufacturing (AM) could enable a more resource-efficient production. However, manufacturing costs and process time in additive manufacturing rapidly rise with part size. Thus, the disadvantages of AM and forging operations could be levered by mating both processes to new process chains, allowing to reduce the number of processing steps and to avoid high material waste. Innovative process chains combining these two manufacturing techniques have been put forward recently, but almost no scientific knowledge on such processing route exists. The present study focusses on the design of a novel processing route and presents an investigation of the hot deformation behavior and microstructure evolution of Ti-6Al-4V material, which was produced by means of wire-arc additive manufacturing (WAAM). The microstructure induced by WAAM and its impact on the hot deformation behavior are analyzed. The results show that the proposed processing route appears to allow for similar properties as conventional forging process chains, but may reduce the number of processing steps and increase the material yield.