Medical devices that include a Ni—Ti ternary alloy and methods for their manufacture. The medical devices described herein include at least one part fabricated from the Ni—Ti ternary alloy. In the Ni—Ti alloys, the ternary alloying element is selected to be compatible with Ni—Ti. Example Ni—Ti ternary alloys include nickel (Ni), titanium (Ti), and one or more of tantalum (Ta), hafnium (Hf), vanadium (V), zirconium (Zr), scandium (Sc), or yttrium (Y). By virtue of their compatibility with Ni—Ti, additions of the ternary alloying element(s) may substitute for titanium in the Ni—Ti phase up to the solubility of the ternary element and the remainder can exist as a second phase whose mechanical properties resemble that of the pure ternary element and whose elastic modulus exceeds that of the Ni—Ti matrix.