Tailoring microstructure and performance of WE43MEO magnesium alloy via multi-pass hot rolling and finishing heat treatment towards foils for biomedical support structures

• Hot rolling enables production of WE43MEO foils with thickness of 200 µm or less. • Foils can be produced applying two to five hot rolling passes. • Key recrystallization mechanisms during hot rolling are CDRX and TDRX. • T6 heat treatment improves degradation properties of the foils. • Three-pass T6-treated material is optimal for biodegradable support structures. WE43MEO magnesium foils (thickness ≤ 200 µm) were successfully produced via hot rolling. The initially extruded material was heat treated at 450 °C for 2 h to achieve a more homogenous microstructure. Afterwards the sheets were hot rolled at 480 °C in two to five rolling passes to achieve a uniform thickness of less than 200 µm and finally heat treated (T5 and T6 heat treatment). After foil rolling and final heat treatment the microstructural und texture evolution as well as resulting mechanical properties were investigated. Therefore, the samples were quenched directly after foil rolling and the final heat treatment. The foil rolling led either to a deformation microstructure (two and three passes) or globular grains (four and five passes) depending on the number of rolling passes. As main recrystallisation mechanisms continuous dynamic recrystallisation (CDRX) and twinning induced dynamic recrystallisation (TDRX) were identified. The resulting textures revealed the activation of non-basal slip of < c + a >-dislocations during prior foil rolling. As a result of the rolling, the strength increased and the elongation decreased compared to the extruded and heat-treated state. Furthermore, it was found that a T6 temper increased corrosion resistance of the tested WE43MEO foils.