Magnesium in the 21st Century: A Better Choice for
will become the material of choice as designers strive to improve energy
efficiency in transportation.
As the world supply increases and a new legion of energized researchers and
scientists address the many aspects of the most abundant structural metal,
magnesium will again rebound to new heights. The present trend indicates that
China will be a major contributor to this development.
Novelty, OH (Vocus) February 27, 2009
and its alloys are being considered for structural applications in every type of
vehicle because of their favorable combination of tensile strength, elastic
modulus, and low density, according to ASM International, the materials
In the article ''Magnesium in the 21st Century,'' Robert E. Brown of the
Magnesium Assistance Group Inc., Prattville, Ala., describes magnesium alloys as
having high strength-to-weight ratios and relatively good electrical and thermal
conductivity, as well as high damping capacity.
"Magnesium is the eighth most abundant element in the Earth's crust, and the
third most plentiful element dissolved in seawater," Brown said. "Because
magnesium is found in seawater, it is available in almost limitless quantities:
A cubic mile of seawater contains six million tons of magnesium metal."
Magnesium as a structural material has been "up and down" during the 20th
Century, Brown explained. "As the world supply increases and a new legion of
energized researchers and scientists address the many aspects of the most
abundant structural metal, magnesium will again rebound to new heights. The
present trend indicates that China will be a major contributor to this
Two major magnesium alloy systems are available. The first includes alloys that
contain 2 to 10% aluminum, combined with minor additions of zinc and manganese.
These alloys are widely available at moderate cost, and their mechanical
properties are good at temperatures up to 95 to 120°C (200 to 250°F). However,
above these temperatures properties deteriorate rapidly.
The second group consists of magnesium alloyed with elements such as rare
earths, zinc, thorium, silver, and silicon (but not aluminum), all containing a
small but effective zirconium content that imparts a fine-grain structure (and
thus improved mechanical properties). These alloys generally possess better
elevated-temperature properties, but they are more expensive because of their
more costly elemental additions and specialized manufacturing technology.
Aluminum metal, which is not easy to get from its ores, has become a 30 million
ton per year business, while magnesium has struggled to reach about 800,000 tons
per year. "Realistically, world production must grow to over one million metric
tons per year if it is to be seriously considered for widespread applications,"
The largest amounts of magnesium will continue to be for aluminum alloying, but
Brown expects that it will continue to be needed for desulfurization of steel
''if the price is competitive.'' Interest in magnesium is growing in
technologies such as thixomolding, extrusions, sheet, and forgings. "Magnesium
can also provide huge structural and economic advantages in automotive and
aerospace applications, based on life cycle analysis," Brown said.
''Magnesium in the 21st Century,'' a complete description of the current state
of the magnesium industry and future opportunities, can be accessed and
downloaded free of charge at http://www.asminternational.org/amp .
To access the article directly: http://asmcommunity.asminternational.org/static/Static%20Files/IP/Magazine/AMP/V167/I01/amp16701p31.pdf?authtoken=4311dfd366c81aa2e197c5b22c31baec3e4204c3
ASM International is Everything Material, the Ohio-based society serving the
materials science and engineering community. With 36,000 members worldwide. ASM
provides authoritative information and knowledge on materials and processes from
the structural to the nanoscale. For details, visit http://www.asminternational.org
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