Manufacturing Ti-6Al-4V Aircraft Components at Lower Cost by Combining Beta-Forging and Electron Beam Additive Manufacturing

The MAMA (Metallic Advanced Materials for Aeronautics) project aims to drastically reduce the manufacturing cost of aircraft parts made of Ti-6Al-4V. To achieve that goal, the project is investigating two strategies to cut the input weight of titanium material. The first consists in closed-die-forging above the beta transus temperature, thus allowing a significant flow stress reduction and, at a prescribed forging force, a near-net shape part. To demonstrate the feasibility of beta forging of complex geometries, box-like samples with cross ribs were closed-die-forged under a pilot press previously upgraded for that purpose. In addition, compression tests were performed in the Gleeble3500 thermomechanical simulator to study the mechanical behavior of Ti-6Al-4V above the beta transus temperature. The rheological model resulting from these tests will improve the accuracy of modelling carried out with the FORGE® finite element software. Microstructural changes occurring during such compression tests were investigated using SEM-EBSD technique. The other solution studied is the local addition of material by Electron Beam Additive Manufacturing (EBAM), on a preform forged in the β domain. To validate this technology and pave the way for hybridization trials to come, prototypes capable of the same finished machined shape as the one targeted by the closed-die-forging trials were built onto titanium plates using the Sciaky EBAM technology. Dimensional and metallurgical analysis of these prototypes suggest that hybridization between EBAM and closed-die-forging in beta domain could be a cost-effective alternative to both closed-die-forging and Additive Manufacturing. TRL4 and TRL6 hybrid demonstrators have to be developed later in project MAMA to validate this assumption.