Abstract: The invention relates to a method for producing a grain refiner on the basis of an aluminum-titanium-boron prealloy. According to the inventive method, starting materials that contain Ti and B are introduced into an aluminum melt while TiB2 particles are formed, and the prealloy melt produced is allowed to solidify. The prealloy is set in motion at a temperature between the liquidus temperature (TLAl3Ti) of the Al3Ti phase and the solidus temperature (TSV) of the prealloy for a period (&Dgr;td) sufficient to disperse the TiB2 particles in the melt. The melt is simultaneously cooled off at a first rate of cooling (v1) so that the TiB2 particles function as the nuclei for the Al3Ti phase that is formed below the liquidus temperature (TLAl3Ti) and the surface of the TiB2 particles is at least partially covered by an Al3Ti coating.

Abstract: An aluminium alloy suitable as a material for superplastic forming contains0.8-2.5% or iron,3.5-6.0% of magnesium,0.1-0.6% of manganese,0.05-0.5% of zirconium,at most 6.0% of zinc,at most 3.0% of copper,at most 0.3% of silicon,at most 0.05% of titanium andat most 0.05% of chromium,the remainder being aluminium of commercial purity.The alloy can be processed to give superplastically formable sheets without separate thermomechanical pretreatment.