| Abstract Scope |
Enhanced casting techniques are now demonstrated to raise properties simply by avoiding the formation of defects. The potential for increased properties by eliminating defects appears to exceed by far the capabilities of the usual metallurgical techniques of alloying and heat treatment. It is discovered that precipitates such as carbides in steels do not form on grain boundaries, they form on bifilm cracks (a high proportion of which are at grain boundaries). Closed bifilm cracks are prized open by the precipitation of inclusions, causing the metal to be sensitized to fracture by fatigue, creep, stress corrosion cracking and hydrogen embrittlement. The mysterious fracture feature, the fisheye, is an integral part of the fracture mechanism. Enhanced steels and Al alloys are currently being demonstrated (at reduced cost). For the first time we will be capable of manufacturing metals resistant to failure by fracture, possibly irrespective of mechanism. Metals we can trust. |