The Potential for High Strength Castings

Recent developments relating to casting production have indicated that improvements to ductility, toughness and fracture resistance of several hundred per cent seem attainable. This will be illustrated for Mg and Al alloys, steels and Ni-base superalloys. The essential condition is the control of bifilms which appear to be the initiator (probably the sole initiator) of cracking in metals. Traditionally this major factor controlling properties has remained neglected. Aspects of control and quantification of bifilm content of castings with a view to achieving the proper potential of metals will be outlined.