Microstructural and mechanical properties evaluation of Calcium and zinc-modified WE43-based nanocomposites through stir casting for biodegradable applications

Abstract

Magnesium-based alloys and composites have potential as biodegradable materials due to their moderate biodegradability, biocompatibility, and usefulness, but their mechanical strength limits their clinical use. The study synthesized a WE43-based alloy with calcium (Ca) and zinc (Zn), then reinforced it with nano reinforcements (hydroxyapatite, beta-tricalcium phosphate, graphene, and bioglass) through stir casting to create four nanocomposites. The microstructural and mechanical properties were examined to assess Ca and Zn ' s influence and determine the most effective reinforcement. The result showed that Ca and Zn-modified alloys and all nanocomposite materials have two additional phases, LPSO and Ca 2 Mg 6 Zn 3 , compared to the monolithic WE43 alloy. With the addition of Ca and Zn, S-2 saw significant increases in ultimate tensile strength (UTS), tensile yield strength (TYS), and uniform elongation (U.El), reaching -246 MPa, -144 MPa, and -8 %, respectively, while maintaining an elastic modulus of -19 GPa. This resulted in improvements of -29 %, -25 %, and -9 % compared to the as -cast WE43. Graphene-reinforced S-4 demonstrated superior mechanical properties with a UTS of 294 MPa, TYS of 194 MPa, U.El of -8 %, and an elastic modulus of 24 GPa, representing increases of -52 %, -69 %, and 6.05 %, respectively, compared to as -cast WE43. Additionally, S-4 exhibited impressive compressive properties, with an ultimate compressive strength (UCS) of 370 MPa, a compressive yield strength (CYS) of -185 MPa, and an U.El of -26 %. The bioglass-reinforced nanocomposites had a maximum hardness of 74.8 HV, whereas the as-cast WE43 had a maximum toughness of -4 J. These enhancements in mechanical properties are attributed to strengthening processes, including thermal mismatch, orowan, and grain refinement mechanisms. Graphene reinforcement shows promise for biodegradable applications.