Progress towards high superplastic strain rate aluminium alloys

Earlier work has demonstrated that an Al-4Mg-1Zr alloy made by particulate casting can be processed to give elongations in excess of 600% at a strain rate of 10-2 s-1. However, conventional extrusion was used for consolidation of the particulate and this would, inevitably, result in an unacceptable contribution to the cost of the product. For commercial viability a method of particulate consolidation is required which can produce sheet with sufficiently large strain for the development of SPF properties economically. The paper summarises the earlier work and describes initial experiments employing both direct particle rolling and continuous extrusion.