Performance Improvement of the NiTi Alloy Wire Used for Aortic Stent―graft

In order to improve the physical properties and biocompatibility of the aortic stent―graft, the effects of heat treatment and electrochemical polishing on nickel―titanium (NiTi) alloy wire during the stent―graft preparation were studied. It is found that heat treatment could help shaping the stent―graft and enhance the mechanical properties of the NiTi wire. The ideal heat―treatment process is heating at 480 and 510 for 7 min, respectively. By electrochemical polishing, the surface quality and fatigue life of the wire is highly improved. Meanwhile, electrochemical polishing results in reduction of the possibility of the mural thrombus formation and endothelial hyperplasy.