ALLIAGE DE MAGNESIUM

MAGNESIUM ALLOY

Abrégé français

Alliage de magnésium ayant la composition suivante : manganèse 1,5 à 2,2 cérium 0,5 à 2,0 lanthane 0,2 à 2,0, ces chiffres indiquant le pourcentage en poids pour l'alliage, et le magnésium et les impuretés reliées à la production comptant pour le reste de l'alliage à 100 % en poids.

Abrégé anglais

Magnesium alloy having the composition Manganese 1.5 to 2.2 Cerium 0.5 to 2.0 Lanthanum 0.2 to 2.0, these figures indicating the weight percent for the alloy, and magnesium and production-related impurities accounting for the remainder of the alloy to 100 wt. %.

Revendications

CLAIMS:
1. Magnesium alloy consisting of, by weight,
Manganese 1.5 to 2.2%
Cerium 0.5 to 2.0%
Lanthanum 0.2 to 2.0%,
and the balance magnesium and production-related impurities wherein the alloy
is free of
aluminum.
2. Magnesium alloy in accordance with claim 1,
having a tensile yield strength Rp 0.2 of at least 140 Mpa.
3. A drawn welding rod consisting of the magnesium alloy of claim 1.
4. An extruded or diecast part consisting of a magnesium alloy according to
claim
1.
5. Magnesium alloy in accordance with claim 1, consisting of, by weight,
Manganese 1.8%
Cerium 0.6%
Lanthanum 0.4%,
and at least 97% magnesium, the remainder being production-related
impurities.
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Description

CA 02745861 2011-07-08
Magnesium Alloy
The invention relates to a magnesium alloy for technical applications and to
the use of such an
alloy for producing extruded semi-finished products and components and for
producing sheet.
Magnesium alloys are lightweight materials that are used in automotive
engineering, engine
construction, aerospace engineering, and other lightweight designs.
With very good strength properties and a low specific weight, magnesium alloys
are especially
suitable as metal construction materials for vehicle and aircraft
construction.
Especially in vehicle construction it is necessary to reduce weight because
additional elements
are built in due to rising standards for comfort and safety. Lightweight
construction is also
important for the design of energy-saving vehicles. When processing magnesium
materials, the
methods used - primary shaping by die-casting and shaping by extrusion,
forging, rolling,
stretch-forming or deep-drawing - become increasingly significant. Lightweight
components
that are enjoying increasing demand, especially for vehicle construction, can
be produced using
these methods.
Known from DE 806 0055 is a magnesium alloy that constitutes a composition of
0.5 to 10%
metals from the group of rare earths, and the remainder magnesium, with the
provision that the
rare earths constitute at least 50%, preferably at least 75% neodymium, at
most up to 25%
lanthanum and cerium separately or together, and praseodym and small
quantities of samarium
and traces of the elements of the yttrium group as the remainder, one or a
plurality of the
following elements being added: manganese, aluminum, calcium, thorium,
mercury, beryllium,
zinc, cadmium, and zirconium.

CA 02745861 2011-07-08
Known from DE 42 08 504 Al is a magnesium alloy that contains 2 to 8% rare
earth metals, the
rare earth metal comprising samarium.
Other alloys that in addition to the main component include magnesium,
manganese, and other
elements from the group of the sp metals and/or aluminum, copper, iron,
nickel, calcium, etc.,
are known for instance from DE 199 15 276 Al, DE 196 38 764 Al, DE 679 156, DE
697 04
801 T2, DE 44 46 898 Al.
The known magnesium alloys have various disadvantages.
In the presence of calcium, heat cracks can occur after casting in a casting
process that has a
rapid cooling speed, for instance injection molding. The strength of alloys
that include
magnesium-aluminum-zinc-manganese or magnesium-aluminum-manganese declines at
higher
temperatures.
Overall the shaping behavior, weldability, and resistance to corrosion
deteriorate.
The cold formability of the most common magnesium alloys is limited due to
their hexagonal
crystal structure and low ductility. Most magnesium alloys are brittle at room
temperature. For
certain shaping methods for producing semi-finished products from magnesium
alloys, ductility
is necessary in addition to high tensile strength. Higher ductility enables
improved shaping and
forming, and sometimes also higher strength and toughness. Many of the known
magnesium
alloys have properties that vary widely with the production condition.
The object of the invention is to develop a magnesium alloy that is suitable
for producing sheet,
welding rod, extrusion and/or diecast profiles or components, that is, that
has good forming
properties, high resistance to corrosion, improved weldability, a high yield
point, and good cold
formability.
This is inventively attained using a magnesium alloy having the composition
2

CA 02745861 2011-07-08
Manganese 1.5 to 2.2
Cerium 0.5 to 2.0
Lanthanum 0.2 to 2.0,
these figures indicating the weight percent (wt. %) for the alloy, and
magnesium and production-
related impurities accounting for the remainder of the alloy to 100 wt. %.
The magnesium alloy has a tensile yield strength Rp 0.2 of at least 140 Mpa
and good strength
properties across a wide range of temperatures and has a high creep resistance
with adequate
formability.
The inventive magnesium alloy can be used for producing sheet, semi-finished
products, or
extrusion and/or diecast parts and profiles and for producing welding rods.
These can then be
used to produce special parts, preferably for use in vehicle construction,
train construction, ship-
building, and aircraft construction, such as seat, window, and door frames,
vehicle outer skins,
housings, supports, mounts, columns, and other small parts.
One particularly advantageous composition of the inventive magnesium alloy
results when it
comprises the components 97% magnesium, 1.8% manganese, 0.6% cerium, and 0.4%
lanthanum, the remainder being production-related impurities.
The alloy having this composition is distinguished by good corrosion
resistance, improved cold
forming behavior, low warm creep behavior, and a high tensile yield point.
This magnesium alloy can be used in particular for producing sheet, extrusion
and/or diecast
profiles and components, and for producing drawn welding rods.
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