BMW Pushes Lightweight Technology with Magnesium
Magnesium: A Material with Great Perspectives
- BMW Group developing new, trendsetting options for the use
- World's first composite magnesium/aluminum crankcase for a water-cooled engine; magnesium alloy with new features and properties.
- Landshut Plant acting as the Competence Center for Light-Alloy Casting
in building the instrument panel structure for Rolls-Royce.
- Leadership in production technology thanks to in-house know-how.
Magnesium is not only one of the most common elements in the world, but can also be recovered, inter alia, through electrolysis. In its pure form, with a density of 1.81 grams per cubic centimeter, magnesium offers a significant advantage over both aluminum (density 2.68 grams/cubic centimeter) and steel (density 7.87 grams/cubic centimeter) in terms of weight.
Magnesium: the ideal lightweight material?
Magnesium nevertheless has some features, which limit its possible use in the automobile. Whenever it comes into contact when wet with other materials such as iron, for example, magnesium is subject to a greater risk of corrosion. Depending on the alloy used, a further point is that magnesium may tend to creep under load at high temperatures. This is why magnesium in its pure form or as a conventional alloy is not suited for permanently conveying high loads and forces of the kind typically encountered in central components of the engine. So far the use of conventional magnesium alloys has been limited to components and applications subject to only a minor risk of corrosion as well as thermal or mechanical loads kept to a minimum.
A milestone in lightweight technology: the world's first composite magnesium/aluminum crankcase
In the meantime the BMW Group has made a genuine breakthrough in technology, developing the world's first composite crankcase made of magnesium with a cast-in aluminum insert. This makes the BMW Group the first manufacturer of a water-cooled combustion engine using the substantial weight benefits of magnesium and at the same time overcoming the drawbacks of this very light material. This composite crankcase for a straight-six power unit is a series-based development scheduled to enter regular production in BMW power units in the next two years.
: BMW Plant Landshut. Composite magnesium aluminum crankcase schematic diagram.