1, titanium alloy: mainly used to replace bones, joints and so on.
2, titanium-nickel alloy shape memory alloy: mainly used for heart stents, pacemakers, orthodontic teeth and so on.
3, martensitic stainless steel: mainly due to medical equipment, scalpels, syringes needles and so on.
Of course, as a medical device, almost any metal materials have applications, medical equipment, different parts of the application of different metal materials. Then again, radioactive metals are used in chemotherapy for cancer treatment and so on.