Abstract: A process is disclosed for the production of cast cylinder heads made of aluminium alloys from at least two different "liquid" alloys. The liquid alloys at the time of casting may contain solid particles of varied size and shape so as to produce composites with a metal matrix after solidifying. The process for moulding composite cylinder heads includes a number of successive layers consisting of at least two different alloys and consists in casting each alloy layer in the cavity of a mould via a feed system with a waiting time between the end of casting of one layer and the beginning of the second layer, so that the first layer contains between 50 and 100% of solid fraction in its lower part and 0 to 80% of solid fraction in the upper part, the interface region, when the second alloy is introduced.

Abstract: The invention relates to sheets of aluminium alloy containing magnesium, suitable for producing bodies of cans by drawing and ironing, and a method of obtaining said sheets.The sheets are characterized in that they have, over 10 to 25% of their surface, uniformly distributed particles formed by amorphous aluminium oxides and crystalline magnesium and aluminium oxides, in the form of flat discs less than 5 microns thick and with a mean diameter distributed round a means value from 2 to 15 microns.One of the methods of obtaining said sheets is characterized in that the strip is taken as it comes from the casting machine or after at least one rolling pass and subjected to chemical etching so as to reduce its thickness by a maximum of 2 microns, before being annealed in air at from 330.degree. to 450.degree. C. for at least 30 minutes.