Scientists have devised a new metal alloy, made by mixing titanium and gold, that could lead to a revolution in how prosthetics are designed. Described in the journal Science Advances, the breakthrough was made by a team led by Emilia Morosan from Rice University. The alloy is described as being four times stronger than pure titanium, and crucially it could be used in tandem with living tissue. Currently, titanium is preferred for artificial knee and hip joints because of a number of features, including being strong, wear-resistant, and nontoxic. However, current implants have to be replaced after about 10 years due to them degrading. This new alloy would potentially allow for longer-lasting implants, with the researchers suggesting it would wear down 70 percent less than pure titanium. Its four times harder than pure titanium, which is whats currently being used in most dental implants and replacement joints, said Morosan in a statement. This compound is not difficult to make, and its not a new material. Called beta-Ti3Au, the alloy has a ratio of titanium to gold of three to one. Its atoms are tightly packed in a cubic crystalline structure and, although these researchers may not have been its first discoverers, they are the first to document its potential uses. Aside from biomedical applications, the BBC notes that Ti3Au could have uses in drilling, sporting goods, and more. But given that human bone is able to grow firmly around titanium, its obvious initial uses are in artificial joints. The mechanical properties of the intermetallic compound [beta-Ti3Au] suggest that this material is well suited for medical applications where [titanium] is already used, the authors note in their paper. The fourfold increase in hardness, as compared with pure [titanium], renders [beta-Ti3Au] the hardest known biocompatible intermetallic compound.
IFL Science, 25 July 2016 ;http://www.iflscience.com ;