Development of efficient and scalable ultrasound-assisted solidification technologies for manufacturing advanced metallic alloys (Ultra-Cast)

Lead Research Organisation: Brunel University
Department Name: Mechanical and Aerospace Engineering

Abstract

This proposal is submitted in response to the EPSRC Manufacturing the Future Call for Investigator-led Research Projects open on 09 July 2013.

This proposal addresses the urgent need of the metal materials and manufacture industry to search and adopt next-generation, step-change technologies for the manufacturing of primary ingots and/or shaped components with much improved mechanical properties and reliability, less energy consumption and negative environmental impact, e.g. Al and Mg alloys for mass transport applications, consumer products, Ni superalloy for industrial gas turbines (IGTs) for energy generation. At present, our economic competitors are conducting extensive research in this area.

By adopting lighter alloys with better mechanical properties and reliability, mass transport systems can reduce energy consumption, adverse environmental impact, making wider application of alternative fuel schemes possible. While with improved materials performance, IGTs can be operated at a higher temperature duty cycle to increase the efficiency of energy generation.

Casting is one of the most widely used and productive manufacturing technologies for these and other applications. Ultrasonic cavitation treatment offers sustainable, economical and pollution-free solutions to melt processing and casting of conventional and advanced metallic materials with significant improvement in mechanical properties and quality of the products manufactured.

Although demonstrated on a laboratory scale, the ultrasound-assisted casting technique has not yet found widespread industrial application, mostly due to the lack of in-depth understanding of the mechanisms that lead to the macro/microstructure improvement, especially on the mechanisms of enhancing nucleation and crystal multiplication at different stages of solidification processes.

The proposed programme will study the solidification fundamentals of metallic alloys under applied ultrasonic waves, and develop industrial exploitable methodologies to control and optimise the solidified microstructure under the influence of ultrasonic waves. The goal is to realise distinct materials performance improvements in cast products through 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, aiming 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 ultra-high speed imaging studies plus advanced numerical modelling and scale-up experiments performed on real metallic alloys.

The outcomes will be 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 partner, Doncasters Group Ltd, providing industry with the knowledge, methodologies and tools to control microstructure of castings using ultrasound technology.

Publications

10 25 50
 
Description Through a specially developed technique of quenching alloy in the process of ultrasonic process, it was discovered that the ultrasonic cavitation has effects on both nucleation and growth of primary intermetallics in Al-Zr and Al-Ti systems. Nucleation is facilitated on oxides, The growth morphology of primary intermetallics changes as as result of cavitation impact. A thorough examination of nucleation mechanism on oxides and of particle fragmentation is on going through high-resolution electron microscopy, X-ray analysis and high-speed filming. The interaction of cavitation bubbles with intermetallics has been for the first time directly observed in water.A fatigue-type mechanisms of fragmentation by oscillating bubbles has been proposed, A eutectic reaction has been confirmed in diluted Al-Zr alloys (contrary to the adopted view on the peritectic reaction in these alloys).
Exploitation Route This findings provide a useful tool for selecting regimes of ultrasonic properties for metallic alloys and can be used in casting practice. The fragmentation observations give important data for model validation.
Sectors Aerospace, Defence and Marine,Chemicals,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Transport

 
Description The findings have practical and basic value for various fields where cavitation is currently used or can be used, e.g. food and chemical industry (dispersion and fragmentation, emulsification) and metallurgy (dispersion and fragmentation).
First Year Of Impact 2015
Sector Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Transport
Impact Types Economic

 
Description Manchester 
Organisation University of Manchester
Country United Kingdom 
Sector Academic/University 
PI Contribution We involved a team of prof. G., Burke of the University of Manchester in an advanced preparation of samples for studying intermetallics in Al alloys. This resulted in publications.
Collaborator Contribution The contribution of the University of Manchester was thorough the access and assistance in the preparation of TEM samples by FIB.
Impact One paper is published in Acta Materialia and one is submitted to Scripta Materialia.
Start Year 2015
 
Description Moscow 
Organisation National University of Science and Technology MISiS
Country Russian Federation 
Sector Academic/University 
PI Contribution We have invited this expert group in thermochemistry to assist us in the thermal analysis of Al-Zr alloys where we have observed an unusual effect.
Collaborator Contribution Thermochemistry team from Moscow was able to obtain accurate readings of the phase transformation temperatures, enabling us to establish a eutectic reaction in Al-Zr alloys that have been previously considered as peritectic.
Impact As a result of this collaboration one paper has been submitted to Scripta Materialia and one is being prepared to be submitted to a high-ranking journal.
Start Year 2016
 
Description Symposium orgamiser (TMS) 
Form Of Engagement Activity Scientific meeting (conference/symposium etc.)
Part Of Official Scheme? Yes
Type Of Presentation workshop facilitator
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact more than 40 abstracts were received, more than 20 papers submitted, leading scientists agreed to be invited speakers.

It is expected that new collaborations may arise from this forum, also exchange of ideas and networking are the main objectives.
Year(s) Of Engagement Activity 2014
URL http://www.tms.org/meetings/annual-15/AM15home.aspx