Thixoforming of normally wrought aluminium alloys

Thixoforming - or semi-solid processing - is the shaping of metal components in the semi-solid state. The commercial process uses casting alloys such as 356, 357 and A357 and millions of thixoformed automotive parts are produced with these alloys annually. The challenge is to extend thixoforming to higher performance alloys, which are normally wrought. There is growing evidence that the high strength wrought specification aluminium alloys can be successfully thixoformed, perhaps with some minor modifications to composition or indeed some tighter constraints in the bounds allowed in the alloy specification. Considerable development work is required but the prize will be a significant extension in the potential applications of thixoforming. In this paper some of the results obtained from an ongoing systematic study of thixoforming 2000 series, 6000 series and 7000 series alloys will be presented, along with mechanical properties of thixoformed materials.