Development of Advanced Manufacturing Technologies for Repairing Next Generation Aeroengines (DEMAND-REPAIR)

航空航天工业正在努力建立一个可持续的产业，以减少其对环境的影响和对气候变化的影响。用新的部件替换损坏的部件是一件昂贵的事情，如果部件能够修复和重新制造，这是可以避免的。然而，电子束堆焊、高速氧燃料或等离子喷涂等传统技术不适合有效修复下一代零部件。这些工艺的大量热输入会导致热变形和几何变形，并降低机械性能，导致不可接受的安全风险。因此，必须探索新的替代技术来修复这些先进的部件。冷喷涂、高速空气燃料(HVAF)喷涂、超高速激光熔覆(EHL A)和激光金属沉积粉末(LMDP)等新兴技术与传统技术相比，具有较低的热输入，因此被该联盟确定为最有前途的表面工程和添加剂制造技术。所有这些新兴技术都使用粉末原料，其工艺可靠性和沉积质量取决于对粉末性能(成分、微观结构、形貌、粉末粒度分布)的良好控制。Ti-6Al-4V粉末通常是通过气体雾化生产的，导致所需粒度分布的粉末产率较低。这导致了高昂的成本，并限制了许多新兴的修复和添加剂制造技术的采用。制造高价值Ti-6Al-4V粉末的新方法将以低得多的成本生产出粒度分布细小、流动性强的钛粉末。这一过程还有望产生具有新微结构的粉末。虽然重熔颗粒的激光修复过程不那么令人担忧，但这种微观结构的变化预计将增加变形过程中的延展性，因此，显著有利于基于喷雾的HVAF和冷喷涂过程。因此，按需修复项目计划探索新的先进制造技术和创新的钛粉来修复下一代航空发动机部件。

The aerospace industry is working towards building a sustainable industry to reduce its environmental impact and effect on climate change. Replacing damaged parts with the new ones is a costly affair, which can be avoided if the parts can be repaired and remanufactured. However, traditional technologies such as electron beam patch welding or high-velocity-oxy fuel or plasma spray are not suitable to effectively repair next generation parts. The extensive heat input from these processes can cause thermal and geometrical distortions and degrade mechanical properties, resulting in an unacceptable risk to safety.Therefore, new alternative technologies must be explored for repairing such advanced components. The emerging processes of cold spray, high velocity air fuel (HVAF) spray, extreme high speed laser cladding (EHLA) and laser metal deposition-powder (LMDp) have been identified by the consortium as promising surface engineering and additive manufacturing technologies, due to their lower heat input compared with traditional techniques.All of these emerging technologies make use of powder feedstock material, with the process reliability and deposit quality dependent on well-controlled powder properties (composition, microstructure, morphology, powder size distribution). Ti-6Al-4V powders are typically manufactured via gas atomization and result in a low yield of powders in the desired size distribution. This results in high costs and limits the uptake of many emerging repair and additive manufacturing technologies.Novel approaches to manufacture of high value Ti-6Al-4V powders will create highly flowable titanium powders with a fine and narrow size distribution at a much lower cost. The process is also expected to result in powders with novel microstructures. While less of a concern for the laser-based repair processes that re-melt particles, such changes to microstructure are expected to increase ductility during deformation and as such, significantly benefit the spray-based processes of HVAF and cold spray.Therefore, the DEMAND-REPAIR project plans to explore novel advanced manufacturing technologies and innovative titanium powders to repair the next generation aero-engine components.