ISMR February 2023 | Page 17

RESEARCH NEWS

Innovation through collaboration

Driving the Electric Revolution Industrialisation Centres ( DER-IC ) s , Advanced Electric Machines ( AEM ) and Tata Steel are using collaboration to improve the production and efficiency of electric vehicle ( EV ) components , including motors and batteries , in response to global automotive market demand .
“ The UK aims to meet the target of all cars being zero emissions at the tailpipe by 2035 , and no sales of new petrol and diesel cars and vans from 2030 . With over 30 million electric traction motors needed per annum by 2030 to match the global automotive market demand , there is a need to accelerate the development of the manufacturing and production techniques used in electric vehicles of all kinds ,” explained Tata Steel .
The DER-IC funded “ Coil to Core : Supply Chain for Net Zero CO₂ ” ( COCO ) project , is part of the £ 80M Driving the Electric Revolution Challenge from UK Research and Innovation ( UKRI ). It brings together a network of open access facilities to develop a UK PEMD supply chain and will combine “ cost-effective material supply and cold rolling of a new high-strength , non-magnetic steel with mass production process innovations that can deliver patented lamination designs .” Facilities at DER-IC North East are being used to develop manufacturing , assembly and coating processes . Collaborating with DER-IC has allowed AEM to evolve manufacturing process routes and focus on assembly requirements to overcome the scale-up challenge .
In the project , the materials and process developments will
AEM motor .
be applied to the core of an AEM electric machine design that will be free of rare earth magnets and copper , and validated with prototype motor high-speed dynamometer testing . The core technologies of the project can then be applied to other transport , energy and industrial sectors .
AEM and Tata Steel are collaborating to focus on four improvements that they believe are key to the future success of EV :
■ Faster ( Tata Steel has enabled the production of thin-gauge , non-grainoriented strip steels for electric traction motors ).
■ Further ( AEM aims to create a motor which reduces the energy lost through the motor ’ s rotation for energy efficiency and increased vehicle range ).
■ Lower cost ( the aim isn ’ t just that consumers will pay less for the manufacture of the motor but that the cost will be lower for the overall architecture of the vehicle platform ).
■ Greener ( a product that can reuse and recycle as much as possible , avoiding rare earth metals and processes which release high levels of CO₂ ).
The “ COCO ” project consists of six partners : Advanced Electric Machines Limited ; Centre For Process Innovation Limited ; Coventry University ; Newcastle University ; Tata Steel Nederland Technology B . V . and Tata Steel UK Limited . n
www
. der-ic . org . uk

The secret of stronger metals

Researchers at MIT have been able to study exactly what happens as crystal grains in metals form during an extreme deformation process , at the tiniest scales , down to a few nanometres across . The new findings could lead to improved ways of processing to produce better , more consistent properties such as hardness and toughness .
The new findings , made possible by detailed analysis of images from a suite of powerful imaging systems , have been reported in the journal Nature Materials , in a paper by former MIT postdoc Ahmed Tiamiyu ( now assistant professor at the University of Calgary ); MIT professors Christopher Schuh , Keith Nelson and James LeBeau ; former student Edward Pang and current student Xi Chen .
In general , the smaller the grain size , the stronger the resulting metal . Striving to improve strength and toughness by making the grain sizes smaller “ has been an overarching theme in all of metallurgy , in all metals , for the past 80 years ,” said Schuh , Danae and Vasilis Salapatas Professor of Metallurgy .
Metallurgists have long applied a variety of empirically developed methods for reducing the sizes of the grains in a piece of solid metal , through deforming it in one way or another , but it ’ s not easy to make these grains smaller . The primary method is called recrystallization , in which the metal is deformed and heated . This creates many small defects throughout the piece , which are “ highly disordered and all over the place ,” said Schuh .
When the metal is deformed and heated , then all those defects can spontaneously form the nuclei of new crystals . “ You go from this messy soup of defects to freshly new nucleated crystals . And because they ’ re freshly nucleated , they start very small ,” leading to a structure with much smaller grains , Schuh explained .
What ’ s unique about the new work , he said , is determining how this process takes place at very high speed and the smallest scales . New analysis looks at processes that are “ several orders of magnitude faster ” than typical metalforming processes . “ We use a laser to launch metal particles at supersonic speeds ,” Schuh said .
The result was the discovery of what Schuh says is a “ novel pathway ” by which
grains were forming down to the nanometre scale . The new pathway , which they call nano-twinning assisted recrystallization , is a variation of a known phenomenon in metals called twinning , a particular kind of defect in which part of the crystalline structure flips its orientation .
The team found that the higher the rate of these impacts , the more this process took place , leading to ever smaller grains as those nanoscale “ twins ” broke up into new crystal grains .
In the experiments they did using copper , the process of bombarding the surface with these tiny particles at high speed could increase the metal ’ s strength about tenfold . In the experiments , they were able to apply a wide range of imaging and measurements to the exact same particles and impact sites for a multimodal view .
Because the new findings provide guidance about the degree of deformation needed , how fast that deformation takes place and the temperatures to use for maximum effect for any given specific metals or processing methods , they can be directly applied to realworld metals production , Tiamiyu said .
The research was supported by the U . S . Department of Energy , the Office of Naval Research and the Natural Sciences and Engineering Research Council of Canada . n
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