Abstract
The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.
Highlights
Mg–Li alloys have been applied in automatic, 3C (Computer, Communication, ConsumerElectronic) products and communication electronics fields for more than a decade owing to the high specific strength and advantageous formability [1,2,3,4]
According to previous research [23], the dark areas in the figures can be identified as α-Mg phase, and the grey areas as β-Li phase. It appeared that the α-Mg and β-Li phases were elongated along the extrusion direction, while the intermetallic compounds were mainly distributed at the boundaries of the α-Mg and β-Li phases and at the grain boundaries
Dynamic recrystallization leads to grain refinement during hot extrusion, as indicated by the Hall–Petch formula: recrystallization leads to grain refinement during hot extrusion, as indicated by the Hall–Petch formula: σ = σ0 + Kd−1/2 (2)
Summary
Electronic) products and communication electronics fields for more than a decade owing to the high specific strength and advantageous formability [1,2,3,4]. Their poor creep resistance and inferior corrosion resistance usually limit their application [5,6]. Some studies showed that Al can improve the mechanical properties of Mg–Li alloys owing to the formation of intermetallic compounds and a favorable solid-solution strengthening effect [10,11,12,13,14].
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