Microstructural and Mechanical Evaluation of Rapidly Solidified Mg–Zn–Ca–Mn and Mg–Zn–Ca–Zr Melt-Spun Alloys

Document Type

Article

Publication Date

1-1-2025

Abstract

This work presents the preparation of Mg–2.0Zn–0.5Ca–0.4Mn (CZM) and Mg–1.8Zn–0.3Ca–0.2Zr (CZZ) alloys using typical casting or melt-spinning, and each followed by hot extrusion. The as-cast CZM and CZZ alloys comprise well-formed α-Mg grains, characterized by numerous coarse Mg2Ca and Mg6Zn3Ca2 precipitates, a low solute concentration, and a coarse network of precipitates at the grain boundaries (GBs), together with α-Mg + Mg6Zn3Ca2 and α-Mg + Mg2Ca eutectic structures at the GBs triple junctions. The as-cast alloy demonstrates a lower tensile strength (224 MPa) compared to the as-spun alloy (265 MPa) because of these structural characteristics. In comparison, the microstructure of the as-spun CZM and CZZ samples is distinguished by coarse grains encircled by relatively fine grains, indicative of dynamic recrystallization. The elevated strength of the as-spun CZM and CZZ alloys is ascribed to robust refinement of grains strengthening, solution strengthening, and a greater density of smaller precipitates contributing to precipitation strengthening. Fracture study indicates that the as-cast CZM and CZZ alloys exhibit unique ductile dimples, with quasicleavage and cleavage fractures. The fracture characteristics of the as-spun CZM and CZZ alloys continue to display cleavage planes and ductile dimples.

Publication Title

Advanced Engineering Materials

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