Overcoming the strength-ductility trade-off by the combination of static recrystallization and low-temperature heat-treatment in Co-Cr-W-Ni alloy for stent application

Ueki, Kosuke; Yanagihara, Soh; Ueda, Kyosuke; Nakai, Masaaki; Nakano, Takayoshi; Narushima, Takayuki

doi:10.1016/j.msea.2019.138400

Cited by 25 publications

(20 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In ASTM F90 CCWN and Co-28Cr-6Mo (mass pct) alloys, it was experimentally determined that the SIMT e-phase was formed at either grain boundaries or R 3-annealing twin boundaries. [15,17,25,40] The SIMT e-phase was formed at similar sites in the 6Mn alloys in this study.…”

Section: B Effect Of Mn Addition On Ductilitymentioning

confidence: 52%

“…The regression lines calculated from each plot set using the least squares method are shown in the figure. Note that the regression line of the Base alloy was calculated using the data of recrystallized ASTM F90 CCWN alloys reported by Ueki et al [17] and those of the Base-d40 and Base-d147 alloys reported in this study. For both alloys, the 0.2 pct proof stress was linearly related to d À1/2 , indicating that the Hall-Petch relationship in Eq.…”

Section: A Effect Of Mn Addition On Yield Stressmentioning

confidence: 96%

“…In our previous study, the SFE of the Base alloy was calculated using Thermo-Calc (thermodynamic calculation software, database: TCFE9) and was estimated as approximately 25 mJ m À2 at 300 K. [17] Considering the report by Re´my and Pineau, [41] SIMT should not occur and only deformation twinning should occur in the Base alloy. However, in the Base alloys to which a strain of 30 pct or more was applied, the formation of e-phase by SIMT was observed, [17] i.e., in the Co-based alloys, both SIMT and deformation twinning are considered to occur even when the SFE of the alloy is approximately 25 mJ m À2 . From our previous study [17] and calculation results of SFE in the Co-xMn binary system shown in Figure 8, the SFE of 6Mn alloys was expected to be approximately 31 mJ m À2 .…”

Section: B Effect Of Mn Addition On Ductilitymentioning

confidence: 99%

“…Because microstructural evolution such as grain size change, [2,7,8] precipitate formation, [5,[9][10][11][12][13] and phase transformation [14][15][16] occur in CCWN alloys during thermomechanical treatment, it is essential to understand the role of microstructural evolution in improving the mechanical properties of the alloys through microstructural control. [15,[17][18][19][20][21][22][23][24] Ueki et al [17] designed alloys that can achieve high ductility by low-temperature heat treatment (LTHT) at 873 K in addition to high strength by grain refinement via static recrystallization. Improvement of ductility by LTHT has also been reported in biomedical Co-27Cr-6Mo alloys (mass pct).…”

Section: Introductionmentioning

confidence: 99%

“…The SFE of ASTM F90 Co-Cr-W-Ni (Base) alloy at room temperature is approximately 25 mJ m À2 . [17] To achieve low-yield stress and high strength (excellent work-hardening performance) such as TWIP in the Co-based alloy, it is necessary to increase SFE. Therefore, we attempted to add Mn as a c-stabilizing element in order to increase the SFE.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

Yanagihara

Ueki

Ueda

et al. 2021

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

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

show abstract

Section: B Effect Of Mn Addition On Ductilitymentioning

confidence: 52%

Section: A Effect Of Mn Addition On Yield Stressmentioning

confidence: 96%

Section: B Effect Of Mn Addition On Ductilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Yanagihara

Ueki

Ueda

et al. 2021

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

show abstract

Systematic Study on the Microstructures of Biomedical Co–20Cr–15W–10Ni Alloys with Carbon Contents Ranging from 0 to 0.2 mass pct

Friandani,

Ueda,

Narushima

2024

Metall Mater Trans A

View full text Add to dashboard Cite

Herein, the effect of carbon content on the microstructures of Co–20Cr–15W–10Ni (mass pct, CCWN) alloys was systematically studied. For this, CCWN alloys with carbon contents of 0, 0.05, 0.10, and 0.20 mass pct, i.e., 0C, 0.05C, 0.10C, and 0.20C alloys, respectively, were prepared using an induction melting furnace. The as-cast alloys were solution treated at 1523 K for 7.2 ks, followed by cold swaging and heat treatment at 1173 K–1473 K for 0.15–7.2 ks. Consequently, η-phase (M6C-M12C type, M: metallic element) precipitates were detected in the as-cast 0.10C and 0.20C alloys, whereas no precipitates were observed in the 0C and 0.05C alloys. These precipitates were dissolved via a solution treatment. After cold swaging, the ε-phase formed through a strain-induced martensitic transformation in the 0C and 0.05C alloys. Following heat treatment, a single γ-phase matrix was observed in all the alloys, and μ-phase (Co7W6-type) and η-phase precipitates were observed in the 0C and carbon-added alloys, respectively. The precipitation temperature range of the η-phase increased with increasing carbon content. The stability of the precipitates qualitatively conformed with that of the calculated phase diagram. This is the first paper that reports the microstructural changes in CCWN alloys with varying carbon contents.

show abstract

Bimodal grain structures and tensile properties of a biomedical Co–20Cr–15W–10Ni alloy with different pre-strains

Choi

et al. 2020

Rare Met.

View full text Add to dashboard Cite

Overcoming the strength-ductility trade-off by the combination of static recrystallization and low-temperature heat-treatment in Co-Cr-W-Ni alloy for stent application

Cited by 25 publications

References 29 publications

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

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

Systematic Study on the Microstructures of Biomedical Co–20Cr–15W–10Ni Alloys with Carbon Contents Ranging from 0 to 0.2 mass pct

Bimodal grain structures and tensile properties of a biomedical Co–20Cr–15W–10Ni alloy with different pre-strains

Contact Info

Product

Resources

About