Titanium and gold.
Titanium is the leading material for artificial knee and hip joints because it's strong, wear-resistant, and nontoxic, but an unexpected discovery by Rice University physicists shows that the gold standard for artificial joints can be improved with the addition of some actual gold.It's interesting that a relatively soft metal, gold, can help make an already hard metal even harder and more durable.
"It is about three to four times harder than most steels," said Emilia Morosan, the lead scientist on a new study in Science Advances that describes the properties of a 3-to-1 mixture of titanium and gold with a specific atomic structure that imparts hardness. "It's four times harder than pure titanium, which is what's currently being used in most dental implants and replacement joints."
Ain't science wonderful?