RESEARCH NEWS
Research paves the way for stronger alloys
Scientists from the University of Birmingham in the UK have described how microscopic crystals grow and change shape in molten metals as they cool , in research that is breaking new ground in alloy research and paves the way for improving the tensile strength of alloys used in casting and welding .
Their research , published in ‘ Acta Materialia ’, used high-speed synchrotron X-ray tomography to ‘ photograph ’ the changing crystal structures in molten alloys as they cool . The study shows that as aluminium-copper alloy cools , the solidification process starts with the formation of faceted dendrites , which are formed by a layer-by-layer stacking of basic units that are just micrometres in size . These units start out as L-shaped and stack on top of each other like building blocks but , as they cool , they change shape and transform into a U shape and finally a hollowed-out cube , while some of them stacked together to form beautiful dendrites .
The study was led by Dr . Biao Cai , from the University of Birmingham ’ s School of Metallurgy and Materials , whose research has already demonstrated how magnetic fields influence crystal growth .
“ The findings from this new study provide a real insight into what happens at a micro level when an alloy cools , and show the shape of the basic building blocks of crystals in molten alloys . Crystal shape determines the strength of the final alloy and if we can make alloys with finer crystals , we can make stronger alloys . The results are in direct contrast with the classical view of dendrite formation in cooling alloys , and open the door to developing new approaches that can predict and control the formation of intermetallic crystals ,” commented Dr . Cai .
Dr . Cai ’ s previous research has resulted in a novel technology to improve the quality of recycled aluminium by removing iron from molten alloy in a simple , inexpensive process that uses magnets and a temperature gradient . The technology is the subject of a patent application filed by University of Birmingham
Dendrite crystalline structure .
Enterprise . It has also attracted funding from the Midlands Innovation Commercialisation of Research Accelerator and the EPSRC-Impact Acceleration Account , which has enabled Biao to build a large-scale prototype that runs to 1000oC , and uses a 1 Tesla magnet . The prototype is currently being tested using ingots provided by the Tandom Metallurgical Group , which operates an international trading operation from its base in Congleton , Cheshire , where it produces aluminium alloys and master alloys and recycles aluminium products , scraps and dross .
Dr . Cai expects to publish the results of the testing and showcase the demonstrator to industry before the end of the year , with the aim of finding industrial collaborators willing to run tests in foundry settings in combination with existing production lines . Dr . Cai collaborated with scientists at University College London , the University of Greenwich and the Diamond Light Source and European Synchrotron Radiation Facility on the highspeed X-ray tomography .
The road to low-carbon transportation
Vehicle-to-grid charge-points can improve battery life in electric vehicles and reduce carbon emissions and the costs of charging , a UK government-funded project has found . Research from the EV-elocity project , involving academics in the University of Nottingham ’ s Faculty of Engineering , shows that , by careful charging and discharging , EV battery degradation can reduce by one-eighth and , in some situations , up to 450kg of emitted carbon dioxide ( CO₂ ) or £ 400 could be saved per vehicle each year .
“ Vehicle-to-grid ( V2G ) can balance the calendar and cycling aging ( both of which affect the rate of battery degradation ) to optimise the battery condition and improve its health by 8.6-12.3 % over one-year ’ s operation , compared to conventional charging alone – equivalent to one extra year of use ,” said the University of Nottingham in the UK .
“ In cost-terms , V2G tariff optimisation can save around £ 100 per year per charge-point on normal business electricity tariffs , with up to £ 400 saved on a smarter tariff ,” it added .
If managed to maximise the environmental benefit , nearly half a tonne of annual CO₂ emissions could be saved , with significant savings of over 180kg possible ( even when reducing cost is the main goal ), explained the university .
Chris Rimmer , infrastructure strategy lead at Cenex and lead project manager , said : “ Our conclusions show that it is not necessary to trade-off financial , environmental and asset lifetimes when charging electric vehicles . Cost , carbon and conditioning benefits can all be gained when V2G is used intelligently with fleet vehicles .”
“ A key challenge for optimum application of V2G technology is to synchronise the needs and requirements of the users and the energy and transport systems ,” explained Professor Lucelia Rodrigues , Professor of Sustainable and Resilient Cities . “ Our work correlated variables such as user needs , mobility patterns and renewable electricity generation to evolve different possible scenarios for the application of V2G chargers , with a view to maximising local renewable energy consumption , lowering costs for the user , improving battery life and reducing carbon emissions from the whole system .” The EV-elocity Project was funded by Innovate UK , the Department for Business ,
Energy and Industrial Strategy , and the Office for Zero Emission Vehicles between September 2018 and January 2022 . It was led by Cenex and comprised CrowdCharge ; Leeds City Council ; Nottingham City Council ; University of Nottingham and University of Warwick in a second phase from January 2020 . The project deployed 15 chargepoints across nine sites . Two chargers from eNovates and Nichicon were managed by a technology-agnostic operating system , demonstrating V2G across different trial sites within the UK . The final report presents the findings and lessons learned for future vehicle-to-grid deployment .
“ Our experimental research highlighted the potential to extend battery life by exploiting the unique capability of V2G chargers to both charge and discharge the vehicle battery ,” commented Professor James Marco of Warwick Manufacturing Group . “ By careful optimisation of this process and knowledge of how battery performance may degrade over time , it is possible to condition the battery to extend its life in a number of situations compared to conventional methods of vehicle charging .” n
18 | www . ismr . net | ISMR July / August 2022