Evaluate the use of Elgiloy (Co-Cr-Ni alloy) for wave springs in implantable medical devices.

Elgiloy is the gold standard for implantable medical wave springs due to its biocompatibility, extreme fatigue resistance, and non-magnetic properties. It exhibits a high UTS of up to 2600 MPa after cold work and aging. Its modulus of elasticity ($E = 190$ GPa) is stable across a wide temperature range. In medical pumps, Elgiloy's resistance to pitting and crevice corrosion in saline environments (body fluids) outperforms 316L stainless steel. The processing involves a cold-reduction of approx 85% followed by aging at $500^∘C$ for 5 hours. This creates a dense dislocation network that prevents the initiation of micro-cracks during the millions of cycles required for heart-assist devices.