Abstract: The invention provides a method of die-casting of metals, with dispersion of predetermined quantities of solid particles in resulting metal castings. This is achieved by inserting a cartridge into the runner system, which cartridge is normally sealed at both ends with foil and contains the predetermined quantity of the solid particles. When molten metal is injected through the runner system and thus through the cartridge, it entrains the solid particles therewith which are thereby intermixed with the molten metal and form the composite material of which the die-cast part is thus made. The cartridge is preferably formed of the same metal as the one used for the die-casting, so that it may then be recycled.