Development of efficient & scalable ultrasound-assisted solidification technologies for metal alloys

Project Description

This proposal is timely addressing the urgent need of the metal materials and manufacture industry to search and adopt next-generation, step-change technologies to manufacture primary ingots or shaped components with improved mechanical properties, less energy consumption and negative environmental impact, e.g. Al- and Mg-based materials for mass transport applications, consumer products, Ni superalloy for industrial gas turbines (IGTs) for energy generation, etc. At the moment, our economic competitors, e.g. USA and China, are conducting extensive scientific research in this area. Adopting lighter weight materials with better mechanical and service properties, mass transport systems can reduce energy consumption, adverse environmental impact, and enable wider application of alternative fuel schemes, while with improved materials performance, IGTs can be operated at a higher temperature duty cycle and increase the efficiency of energy generation. Casting is one of the most widely used and productive manufacturing technologies for these and other applications. However, the properties of castings are generally inferior to those of more expensive wrought counterparts. Ultrasonic cavitation treatment offers sustainable, economical and pollution-free solutions to melt processing of conventional and advanced metallic materials with significant improvement in mechanical properties and quality of the products manufactured. Although demonstrated on laboratory scale, the ultrasound-assisted casting technique has not yet found wide industrial applications, mostly due to the lack of in-depth understanding of the controlling mechanisms that lead to the macro/microstructure improvement, especially on the mechanisms of enhancing nucleation and/or crystal multiplication at different stages of solidification process. The proposed programme will study the solidification fundamentals of metallic alloys under applied ultrasonic waves, and develop approaches to control and optimise solidified microstructure under ultrasonic waves and to realise materials performance improvement, in particular by microstructure refinement, increased chemical and microstructural homogeneity and the reduction of solidification defects in primary ingots and shaped castings. The proposed research is ambitious and challenging, and aim to study not only the fundamental mechanisms but also to establish practical methodologies of using ultrasound to promote grain nucleation and multiplication during different stages of solidification in metallic alloys. The novelty of the research is a combination of state-of-the-art in-situ real time characterisation plus advanced numerical modelling and scale-up experiments performed on real metallic alloys. The outcomes of the research will produce new knowledge and novel technological guidelines with their validity demonstrated using commercial alloys and castings produced in the pilot- and industrial-scale facilities of the EPSRC Innovative Manufacturing Centre in Liquid Metal Engineering (LiME) and industry partners, i.e. Doncasters plants, providing industry with the knowledge and tools to control microstructure of castings using ultrasound technology.