Improving the Precipitation Hardness of Ductile Magnesium Alloys by Twin Roll Casting

초록

The challenge implementing magnesium sheets as a lightweight material is to manufacture sheets with an acceptable formability at room temperature and sheet components with a suitable strength. The aim of this work is qualifying suitable alloys and their manufacturing process in a way that precipitation hardening is enabled after the final forming process. The precipitation morphology and the rapid solidification obtained by twin roll casting process are used to find an optimum microstructure for deep drawing and to increase the strength of the formed component by heat treatment. The results show that magnesium sheets made from Mg-Zn-Al-Ca exhibit good forming properties even after rolling from the slab, as well as an increase in hardness after a suitable heat treatment. The production route of sheets via twin roll casting process exhibits higher increases in both ductility of the sheets and hardness after heat treatment compared to the production route via ingot-rolling. This paper presents results of rolling experiments with different feedstock of Mg-Zn-Al-Ca alloys, the microstructures and textures, as well as their mechanical properties and Erichsen values. In addition, various heat treatments were carried out to increase hardness. The second part of the paper deals with the development of a suitable heated deep-drawing tool and shows the heat distribution in the tool as well as first results of the deep-drawing tests. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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