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

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

Abstract

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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 For the first time in this project, we were able to observe in situ the cavitation-driven fragmentation of real intermetallic particles and demonstrate that this process is not instantaneous but rather fatigue-like. Currently, this direction of research is being developed within another project UltraMewtl2 with more sophisticated analysis. This discovery helps in determining the regimes of ultrasonic melt processing (pressure, time). Another major finding is that the nucleation of intermetallics on oxides has been confirmed experimentally and opened the way of using oxides as a structure-controlling medium. The role of Zr in ultrasonic-aided structure refinement has been explained and led to a number of follow-up papers. A possible eutectic type solidification in Al-rich alloys has been suggested and the (previously unclear) roles of ultrasonic processing and small additions of Ti have been explained by their effect on the Al-Zr eutectics. This project also pioneered a number of research techniques for in-situ observations of ultrasonic-affected nucleation and fragmentation, which are currently widely used by our research groups in studying of a wider range of materials, including graphene. 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