Development of Low-Yield Stress Co–Cr–W–Ni Alloy by Adding 6 Mass Pct Mn for Balloon-Expandable Stents

Abstract This is the first report presenting development of a Co–Cr–W–Ni–Mn alloy by adding 6 mass pct Mn to ASTM F90 Co–20Cr–15W–10Ni (CCWN, pct) for use as balloon-expandable stents with an excellent balance mechanical properties and corrosion resistance. The effects addition on microstructures well were investigated after hot forging, solution treatment, swaging, static recrystallization. Mn-added grain size ~ 20 µ m (recrystallization condition: 1523 K, 150 seconds) exhibited ultimate tensile strength 1131 MPa, 0.2 proof stress 535 plastic elongation 66 pct. Additionally, it higher ductility lower yield while maintaining high compared CCWN alloy. formation intersecting stacking faults was suppressed increasing fault energy (SFE) addition, resulting in stress. low-yield effective suppressing stent recoil. In strain-induced martensitic transformation during deformation SFE, thereby improving ductility. alloys also good resistance, similar Co–Cr–W–Ni are suitable stents.