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Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/) eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. (2016) Materials and Design 92 Abstract Electrically-assisted incremental sheet forming (E-ISF) is an effective method to improve materialformability by introducing the electric current in ISF process. This method is particularly useful for fabrication of conventional lightweight 'hard-to-form' materials such as magnesium and titanium alloys. However, the use of electricity and heat in the forming process may also introduce side effects to formed components, such as unsatisfied surface finish. In this work, an improved E-DSIF process has been developed by combining the double sided incremental forming (DSIF) and the electrically-assisted forming technology. Different types of forming tools and toolpath strategies are explored to improve surface finish and geometrical accuracy based on a customized DSIF machine. AZ31B magnesium alloy sheets are formed into a truncated cone shape to verify the proposed approaches. According to the comparative studies, the causes of the rough surface finish in the conventional E-ISF process are investigated, and the surface finish is refined by improving the contact condition at tool-sheet interface in the newly developed process. In addition, a hybrid toolpath strategy is proposed to further enhance the geometrical accuracy. The work demonstrates that the two challenging issues in the E-ISF process, surface finish and geometrical accuracy, could be improved by using the enhanced technologies.

The dielectric constant of Co4Nb2O9 shows an obvious upturn below Néel temperature (TN), and the magnetic field enhances this anomaly. Thus the magnetodielectric effect exists in the entire temperature region below TN, not only near TN as reported previously. At the same time, the strain exhibits a drop below TN, and the magnetic field suppresses this anomaly, demonstrating magnetoelastic coupling in Co4Nb2O9. The origin of dielectric anomaly and magnetodielectric effect below TN may be related to the phonon mode shifts induced by magnetoelastic coupling.