Magnesium: Commodity or exotic?

Abstract

The structural use of magnesium through the 20th century is briefly reviewed, highlighting fluctuating levels of development and use influenced by military applications in two World Wars. Development of more efficient processes, improved corrosion resistant alloys and availability of lower cost metal now offer potential for major expansion in magnesium consumption in the 21st century. A review of current worldwide use indicates major growth in structural transport applications. Apart from the obvious advantage of light weight, other important attributes making magnesium an attractive contender for transport applications are considered. Requirements for magnesium to compete effectively as a commodity material are reviewed. Key areas for development are commercial transport, aerospace and high performance uses. The most important is commercial transport. Significant developments in alloy technology and applications for die casting are described and more speculative growth in use of wrought components discussed. A similar review and analysis of developments for aerospace and high performance applications is given. Alloys developed and properties achieved differ significantly from those considered for higher volume commercial applications and include highly sophisticated alloying and manufacturing technology. Although the main theme is magnesium's potential as a commodity material, more exotic applications of magnesium alloys are reviewed. These include electrochemical alloys, space and missile applications, composite materials, non-equilibrium alloys and medical uses. Finally, the future priorities for development of technology and applications are examined by reference to a recent UK 'road mapping' exercise, which was in general accord with similar exercises in Japan, Germany and the USA.

Nano-ZnO Particles’ Effect in Improving the Mechanical Response of Mg-3Al-0.4Ce Alloy

“…As Mg has a Hexagonal Close Packed (HCP) crystal structure, at ambient temperatures, deformation is, thus, confined to a few modes such as basal slip and twinning. Due to fracture (transgranular and intergranular) at basal planes or twin zones, pure Mg shows a tendency for low ductility [1]. There is also a tension-compression yield asymmetry, and a significant difference in tensile and compressive yield strengths exhibited by Mg, which narrows the opportunities of Mg in structural applications.…”

“…Thus, obtaining nanocomposites with <1% porosity was achieved and is accredited to the secondary processing (extrusion and the extrusion ratio). Mg-3Al-0.4Ce 1.759 ± 0.013 1.762 0.201 6.5 ± 1.5 Mg-3Al-0.4Ce-1.5ZnO 1.779 ± 0.012 (↑ 1.13%) 1 1.781 0.120 6.4 ± 1.5 Mg-3Al-0.4Ce-2ZnO…”

“…The extraction and utilization of magnesium (Mg) in significant amounts started only in the 20th century, despite the fact that the discovery of Mg by Sir H. Davy dates back to 1808 [1]. Mg, with a density of 1.738 g/cm 3 , is one of the lightest engineering and structural metals available on the earth, with its density being about two-thirds that of aluminium and one-fourth that of steel [2].…”

“…Despite several extensive research studies and characterizations on magnesium-aluminium alloys, the main focus was laid on specific materials, such as AZ31, AZ61, and AZ91 [1]. Other potential alloying elements with Mg would be rare earth (RE) metals, which have been known for many years [1].…”

“…There is also a tension-compression yield asymmetry, and a significant difference in tensile and compressive yield strengths exhibited by Mg, which narrows the opportunities of Mg in structural applications. To circumvent these limitations, Mg is alloyed with other elements, such as aluminium, zinc, zirconium, rare earths, etc., to improve strength, ductility, corrosion resistance, and other properties [1].…”