A group of "super-alloys", with properties such as ultra-high-strength, super elasticity and super plasticity, has been discovered by researchers at the Toyota Central Research and Development Laboratories and the University of Tokyo. The alloys show their "super" behaviour over a wide range of temperatures, including room temperature.
The researchers have used computational methods to find their way through a myriad of possible combinations of elements that could lead to useful alloys. In particular, they have found that three electronic "magic numbers" yield the super-alloys: an electron-to-atom ratio of about 4.24; a "bond order", which represents the bonding strength, of 2.87; and a d-orbital energy level, which represents the electronegativity, of about 2.45. The "super" properties arise only when all three numbers are satisfied.
The alloys found in this way are based on titanium, with additional amounts of tantalum, niobium, zirconium, vanadium and oxygen in a simple body-centred cubic structure. To exhibit their "super" properties, the alloys must first be "cold worked", but afterwards they show high strength, together with low expansion and no change in elasticity, over a temperature range of several hundred degrees.
Further reading
Takashi Saito et al. 2003 Science 300 464.