Many bone implants (such as for hips and teeth) need to be replaced after a decade simply because they're not strong enough to survive for any longer. Rice University might put an end to those regular surgeries, though. Its researchers have crafted a titanium-gold alloy that's the strongest ever to be friendly to organic tissue -- four times stronger than pure titanium, and so strong that the team had trouble grinding it into a powder to check its purity. They created it by preparing titanium-3-gold (that is, three parts titanium for every one part of gold) at a high temperature, forming an extremely sturdy crystal structure.