Magnesium (Mg) is an alkaline earth metal having atomic number 12 with oxidation number +2.
Density at 20°C (g/cm3) Magnesum 1.74 Aluminium 2.70 Iron 7.86
The cost of magnesium has been decreasing below the cost of the aluminium since 2004. M
agnesium melting cost is 2/3 compared to aluminium. In terms of productivity, magnesium provides 25% higher casting productivity compared to aluminium pressure die casting, 300- 500% compared to aluminium permanent mold casting, and 200% compared to polymer injection molding.
Magnesium is considered to be a good choice material in the areas of defense and aerospace engineering for aircraft and missile components, aircraft engine mounts, control hinges, fuel tanks, wings. In automotive sector magnesium is used for wheels, housings, transmission cases, engine blocks, steering wheels and columns, seat frames, electronic goods like laptops, televisions, cell phones and in many more areas (http://www.intlmag.org/).
ASTM (American Society for Testing and Materials) names the Magnesium alloys with two letters
defining the elements, with numbers denoting the percentage and an additional digit to indicate intermediate properties.
An ASTM code for magnesium’s alloying elements
Letter Alloying Element Letter Alloying Element
A Aluminum L Lithium
B Bismuth M Manganese
C Copper N Nickel
D Cadmium P Lead
E Rare Earths Q Silver
F Iron R Chromium
H Thorium S Silicon
For example, AZ 91 Mg alloy contain aluminum (Al) and zinc (Zn) in 9%, 1% respectively in total and the rest by pure magnesium.
Magnesium and Its Alloys in Automotive Applications – A Review
D. Sameer Kumar, C. Tara Sasanka, K. Ravindra, K.N.S. Suman
American Journal of Materials Science and Technology
(2015) Vol. 4 No. 1 pp. 12-30
Interviewed engineering graduates for four days during 28 to 31 March 2017. They do not know the usage of magnesium in mechanical engineering product components.
Global demand for magnesium metal will reach 1,085 KT in 2016, representing market value worth US$ 3.13 Bn.
Magnesium’s applications in making automotive wheels, transmission cases, and engine blocks will continue to fuel demand in 2016 and beyond.
Application-wise, magnesium alloys and die-casting will continue to remain the largest segments, accounting for 349 KT and 302 KT respectively in 2016.
Magnesium will continue to witness stable demand from the aerospace sector, owing to its excellent properties as a reductant in manufacturing titanium.
The global magnesium metal market is anticipated to increase at a CAGR of 7.1% during 2016-2026, reaching 6.2 Bn in revenues by 2026.
The automotive and transportation industries is one of the largest end-users for magnesium die-cast components such as assemblies, housings, and brackets. Average use of magnesium per vehicle is about two to three kilograms which could also go as high as 26 kilograms for some vehicles.
Magnesium Alloys: The Future for Automotive Lightweighting?
Experts gathered at the University of Waterloo discussed the challenges and opportunities ultralightweight alloys pose
Magnesium alloys are very attractive for a range of weight-sensitive applications. They have the largest strength-to-weight ratio of the common structural metals, are lighter than aluminum and are particularly favored for being easy to machine and for their ability to be die cast to net shape. Unfortunately, magnesium alloys tend to corrode too easily. A team at Monash University in Australia has now discovered a novel and potentially game-changing approach to the problem: poisoning the chemical reactions leading to corrosion of magnesium alloys by adding a dash of arsenic to the recipe.
Magnesium alloys are of great interest as lightweight replacements for aluminum, titanium, and steel components in a range of transportation and aerospace applications. However, magnesium alloys corrode easily, and this often prevents their use as substitute for noncorroding metals. As a result, the use of magnesium alloys at present is less than a million tons per year, while nearly 50 million tons of aluminum alloys are used each year. The experimental demonstration of reduction in corrosion of magnesium is a welcome step. The result was that addition of about one-third of a percent of arsenic to the magnesium alloy reduced its corrosion rate in a salt solution by a factor of nearly ten. In this initial study the intent was to prove the principle of the use of cathodic poisoning to reduce corrosion of Magnesium.
Updated 1 April 2017, 14 January 2015