High strength Magnesium alloys

Magnesium is of interest as a construction material because of its very low density and good strength. Magnesium is also an excellent casting material. From disadvantage is the low corrosion resistance. New Magnesium alloys are melted with higher purity and have a better corrosion resistance. The corrosion resistance is also influenced by the alloying elements. The use of Magnesium for automotive application has increased in recent years. As casting material for instrument panel beams, seat frames, steering wheels and engine components like valve covers. For Aerospace application the ease of ignition and low corrosion resistance is the major hurdle for a more widespread use. However for Helicopter gear-boxes it is in use.

Because Density is one of the most important property for designing lightweight components the research for Magnesium alloys with improved properties is ongoing. In recent years significant progress has made.

High strength Magnesium alloys could be principally made via two processing routes. First with rare-earth alloying elements, second with rapidly solidifying or a combination of both. The alloying elements Gadolinium and Yttrium are very effective to increase temperature strength. From disadvantage is the fact that they are expensive and increase the density. From this viewpoint it makes sense to improve the processing of Magnesium alloys.

 

Processing of high strength Magnesium alloys

Spray forming

 

Spray forming could be also used for Magnesium production. The spray forming process has a higher cooling rate than wrought metallurgy. Spray formed Magnesium alloys show finer microstructure and higher strength. However the process is not fully commercialized. The size is limited to around 80 mm dia. and 340 mm length.

 

Powder metallurgy

 

Powder metallurgy is in use since many years for the production of Magnesium alloys. The properties vary significantly with the quality of the starting powder and alloy. Cooling rates of Argon gas atomized powders with a Laval nozzle are high. Resulting powder is very fine and show high hardness. This process is also not fully commercialized. But there is no limit in component size because the powder can be filled in large cans. Parts of several hundred Kilograms could be produced. The handling needs some care because of the high reactivity of the not oxidized Magnesium powder. During subsequent processing the powder is canned in Aluminum. This can will e closed via welding. The canned powder will be subsequently extruded, forged or pressed.

 

Melt-Spinning

 

The Melt-Spinning process has very high cooling rates. With this process it is possible to process very high strength Magnesium alloys. The process chain has not been fully commercialized because the powder handling needs to be done under protective atmosphere.

 

Achievable strengths of Magnesium alloys with different processing routes

Process Strength
Wrought up to 350 Mpa
Spray Forming up to 420 Mpa
Powder Metallurgy up to 460 Mpa
Melt-Spinning up to 630 Mpa

Mg-SF42ca

 

Mg-SF42ca is a powder based Magnesium alloy. Despite its high strength Mg-SF42ca shows a ductility of 9%. This alloy can be used for effective lightweight design.

Mg-SF42ca is made via Spray forming. The maximum size of semi finish products is limited. Contact us for the available sizes.

 

Magnesium-Mg-SF42ca
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