Performance-driven design of aluminium alloys for additive manufacturing (PAAM)

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Additive manufacturing (AM) makes net-shaped, highly precise, and cost-effective components of intricate design with minimum waste. However, the AM industry faces many technical challenges in the production of high-quality parts due to intrinsic defects, e.g. pores, cracks, distortions and anisotropy. These microstructural discontinuities are related to the material properties and solidification behaviour upon the AM processing conditions, i.e. rapid melting and cooling. The current developments of AM focus mostly on the printing processing, mitigating intrinsic material's deficiencies by process control, such as laser power and scan speed, and much less on the material side, with a majority of the alloys being originally designed and tailored to suit other manufacturing routes, e.g. casting. The quality of AM parts is dominated by the properties and characteristics of the alloy feedstocks - vital aspects that are currently largely overlooked. As a consequence, there is a limited number of materials that are designed specifically for manufacturing high-quality AM components.The synergetic approach in this project is three-fold and aims to (a) develop a new class of hierarchically structured Al-based alloys with fine-tuned structures and compositions at both the nano- and micro-scale, which satisfy the requirements for cracking resistance, structure uniformity, reduced residual stresses and porosity, enabling a unique combination of properties and dimensional precision for AM; (b) test and optimise their performance upon AM using in situ and ex situ high precision characterisation methods; (c) validate the approach by manufacturing AM test parts with enhanced product quality and, hence, with improved properties and performance. Combining these three advances, we will deliver a new class of high-quality AM materials with lightweight, uniform structure and properties, high rigidity, thermal stability, and designed functionality; combining the best processing features of existing diverse alloy groups.While addressing the challenges of AM through dedicated material development, this proposal has a strong and credible pathway to impact other manufacturing processes, e.g. casting and powder metallurgy using the same alloy design paradigm.