AbstractIn the 30th and 40th and also in the late 80th of the last century there was a rapid increase in use of
magnesium alloys in automotive industry. Magnesium alloy gearbox housings and engine blocks
were produced by chill casting, as a result of the relatively low engine temperatures the alloys
proved adequate. Development of modern water-cooled engines increased the application
temperature and magnesium alloys were replaced by cast iron and aluminium alloys because of the
limited strength and creep resistance of magnesium alloys at higher temperatures. At the end of the
last century alloy development as well as development of magnesium based metal matrix
composites (MMCs) was carried out to improve the high temperature strength and creep resistance.
Alloy development occurred in several directions; either the reduction of aluminum and the addition
of elements that preferentially combine with aluminum or the complete elimination of aluminum as
an alloying element. The need to eliminate or to reduce the aluminum content is because it is known
that b phase (Mg17Al12) contributes to the poor creep resistance in aluminum containing alloys.
From the aluminum containing magnesium high-pressure-die-casting (HPDC) alloys, AE42
currently shows the best creep properties. This is due to the Al-RE precipitates, which suppress the
formation of Mg17Al12.