Microstructure and Mechanical Properties of Extruded Magnesium-Aluminum-Cerium Alloy Tubes

Abstract

Current commercial magnesium extrusion alloys do not offer desirable combinations of strength, ductility, and extrusion speed for automotive structural applications. The effect of small additions of cerium (Ce) to pure magnesium (Mg) and Mg-3 pct Al alloy extruded tubes has been studied. The results suggest that 0.2 pct Ce addition can significantly improve the extrudability and mechanical properties of the Mg extrusions. The improvement in mechanical properties is due to grain refinement and dispersion strengthening provided by the Mg 12 Ce particles and the beneficial texture obtained. Higher Ce contents further increase strength, but significantly reduce ductility and cause excessive surface oxidation during extrusion. The beneficial effect of 0.2 pct Ce on mechanical properties of pure Mg is not observed when it is added to Mg-3 pct Al alloy, due to the higher affinity of Ce to Al to form the Al 11 Ce 3 phase in the MgAl-Ce ternary alloys. The Mg-0.2 pct Ce alloy is a promising base alloy for further development in automotive applications; however, Al should be avoided in Mg-Ce-based extrusion alloys.

Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications

“…15 potential difference [61]. Additionally, Al-Ce phase exhibits passivation in a wide range of pH, which further retards the corrosion of Mg alloys [49].…”

Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review

“…Chino et al [23] claimed that the improvement in ductility due to 0.2%Ce addition as compared to pure Mg is due to the increase in stacking fault energy unlike reduction in c/a ratio that led towards basal/non basal slip activation. Luo et al [24] reported that the addition of 0.5% Ce to Mg resulted in more surface oxidation during extrusion and reduction in ductility and increase in strength. The authors also suggested that Ce concentration should not be higher than 0.5% in extruded alloys due to the excessive surface oxidation during extrusion.…”

“…Luo et al [24] reported that the addition of 0.2 or 0.5% Ce to Mg-3Al did not show significant improvement in tensile properties due to the affinity of Ce for Al thus forming Al11Ce3 in Mg-Al-Ce ternary alloys resulting in the properties as shown in Table 11. …”

Prediction of the True Stress of ZE20 Magnesium Alloy at Different Temperatures and Strain Rates

“…Their studies showed that by adding a small amount of zinc, the strength of the Mg-Ce alloy can be improved notably. Luo et al [5] also examined the microstructure and mechanical properties of extruded magnesium alloy tubes; the results revealed that the mechanical properties can be improved with the addition of Ce to pure magnesium. Chino et al [6] investigated the compressive properties of Mg alloys from room temperature up to 500 °C to understand the effects of Ce on the deformation process; the results showed that the addition of Ce increased the ductility of Mg alloy at room temperature, but decreased it at 300 °C.…”

“…Several gene-expressing programming (GEP) approaches have been conducted and reported in the literature, but it is important to note that a predictive GEP model for the deformation behaviour of a magnesium alloy has not been reported in literature and is the subject of this study. In the current study, the formability of the ZE20 magnesium alloy, which was recently developed by General Motors [4] and [5], was studied. After compression tests of the alloy, the ANN and GEP models were developed to predict the true stress curves of the alloy.…”