Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 3: Microstructures and Phase Transformations: Metals & Alloys

MM 3.9: Vortrag

Montag, 5. September 2022, 12:30–12:45, H45

Microstructural characteristics of lean magnesium alloys — •Tatiana Akhmetshina, Leopold Berger, Samuel Montibeller, Robin E. Schäublin, and Jörg F. Löffler — Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland

Lean magnesium alloys with less than 1 at.% of alloying elements are of high interest for biodegradable implant applications, where the implant remains only temporarily in the body, but degrades after it has fulfilled its task. With a specific combination of requirements, such as biocompatibility, appropriate mechanical properties and low degradation rate, such alloy development is still challenging. Here, we tailored the mechanical properties of lean Mg-Ca alloys by hot extrusion. The optimal alloying range was obtained via thermodynamic calculations using Pandat. The alloys were cast and extruded at the same ratio with different speeds and temperatures. A tensile toughness of up to 76 MJ/m³ was obtained, indicating a superior combination of strength and ductility. Depending on the extrusion parameters, the alloys exhibit a tensile strength of more than 420 MPa or, alternatively, a high ductility of up to 35% elongation at fracture. To obtain a clear understanding of the relationship between mechanical properties and microstructure, the latter was investigated by SEM, TEM and EBSD, focusing on precipitation, grain morphology, and dislocation structure. The grain size varied from submicrometer to several tens of micrometers. Apart from weak texture, the most ductile materials revealed an intriguing activation of <c+a> pyramidal slip.