Integrated Computational Materials, Process and Product Engineering – IC-MPPE 2022

Every industry is driven by cost-efficiency. Although securing quality and safety marks the top priority in the aerospace industry the pressure for a cost-efficient supply chain grown steadily, especially for high cost components like titanium forgings. One significant impact on the costs of aerospace components is the material-efficiency, represented by the buy-to-fly ratio. Every saved kilogram of material from ingot and billet manufacturing to the manufacturing of forgings and the final component has a significant effect on the overall costs. With the introduction of additive manufacturing (AM) as a new, fundamentally different manufacturing method, also the microstructure design of already well-established materials could be challenged. As titanium alloys, specifically Ti-6Al-4V, is widely used for structural parts it is especially interesting to focus on optimizing its buy-to-fly ratio using AM. For bigger parts (> 0,5m) wire based technologies like Wire+Arc AM (WAAM) are the most promising to improve the buy-to-fly ratio form seven after conventional forging to potentially two without further topology optimization. As Ti-6Al-4V always shows a beta-microstructure after WAAM the question arises, if an optimized forging route towards beta-microstructure would lead to a similar cost benefit. Indeed, if a beta-microstructure is the goal from the start many processing steps can be skipped and the design of dies can be improved towards optimal near net shape forgings achieving similar cost savings like WAAM. Comparing those two processes geometrical (tolerances due to shape and distortion) and metallurgical properties (porosity, microstructure and mechanical properties) have to match customer specifications. This work compares the design and manufacturing challenges between WAAM and beta-forging and shows their differences in respect to their properties.