This paper deals, in the main, with aluminium alloys and steels that are currently available on a commercial basis or are likely to become available in the near future. It highlights the more significant improvements made during the past two decades.

Aircraft structures have been built predominantly of aluminium alloys since the Second World War and, although certain improvements have been made over this period, the alloy systems used have changed little essentially because the alloys available have been limited by the solid solubilities of the selected solute elements at safe solution temperatures. The slow but certain development of novel production routes including fibre and whisker reinforcement of metals, powder production and rapid solidification techniques will circumvent this limitation by the turn of the century.