Biodegradable implants have emerged in biomedical applications,particularly for orthopedic fixations,cardiovascular stents,and tissue engineering scaffolds.Unlike permanent implants,they are designed to degrade and be...Biodegradable implants have emerged in biomedical applications,particularly for orthopedic fixations,cardiovascular stents,and tissue engineering scaffolds.Unlike permanent implants,they are designed to degrade and be reabsorbed after implantation in the body,mitigating the need for additional surgeries and reducing associated complications.In particular,Fe-Mn-C alloys constitute a new class of promising metallic materials for medical applications due to their outstanding mechanical properties and their bio-logical performances.This study focuses on improving the degradation rates and cytotoxicity of sintered Fe-Mn-C alloys produced using the powder metallurgy process.To evaluate the impact of different pow-der preparation methods on material properties,two types of powders were used:(1)MX,prepared by mixing Fe,Mn,and C powders for 1 h;and(2)MM,obtained by mechanically milling the same powders for 10 h.Four mixtures with varying proportions of MX and MM were prepared.Two groups of samples were produced:one entirely from MX(A0),and another containing MM at 25 wt.%(A25),50 wt.%(A50),and 75 wt.%(A75).All samples exhibited a complex microstructure comprising ferrite,martensite,and residual austenite.Degradation behavior assessment in Hanks’solution over 14 days showed that adding MM increased the degradation rate,from around 0.04 mmpy for A0 to 0.12 mmpy for A25.Notably,all samples showed similar cell viability,in the range of 83%-89%for 1%extract dilution,and were non-hemolytic,with a hemolysis percentage below 1%.展开更多
Twinning-induced plasticity(TWIP)steels are considered excellent materials for manufacturing products requiring extremely high mechanical properties for various applications including thin medical devices,such as biod...Twinning-induced plasticity(TWIP)steels are considered excellent materials for manufacturing products requiring extremely high mechanical properties for various applications including thin medical devices,such as biodegradable intravascular stents.It is also proven that the addition of Ag can guarantee an appropriate degradation while implanted in human body without affecting its bioactive properties.In order to develop an optimized manufacturing process for thin stents,the effect of Ag on the recrystallization behavior of TWIP steels needs to be elucidated.This is of major importance since manufacturing stents involves several intermediate recrystallization annealing treatments.In this work,the recrystallization mechanism of two Fe-Mn-C steels with and without Ag was thoroughly investigated by microstructural and mechanical analyses.It was observed that Ag promoted a finer microstructure with a different texture evolution,while the recrystallization kinetics resulted unaffected.The presence of Ag also reduced the effectiveness of the recrystallization treatment.This behavior was attributed to the presence of Ag-rich second phase particles,precipitation of carbides and to the preferential development of grains possessing a{111}orientation upon thermal treatment.The prominence of{111}grains can also give rise to premature twinning,explaining the role of Ag in reducing the ductility of TWIP steels already observed in other works.Furthermore,in vitro biological performances were unaffected by Ag.These findings could allow the design of efficient treatments for supporting the transformation of Fe-Mn-C steels alloyed with Ag into commercial products.展开更多
基金supported by the Natural Science and En-gineering Research Council of Canada(Discovery and Alliance),and PRIMA(Quebec Ministry for Economy and Innovation).
文摘Biodegradable implants have emerged in biomedical applications,particularly for orthopedic fixations,cardiovascular stents,and tissue engineering scaffolds.Unlike permanent implants,they are designed to degrade and be reabsorbed after implantation in the body,mitigating the need for additional surgeries and reducing associated complications.In particular,Fe-Mn-C alloys constitute a new class of promising metallic materials for medical applications due to their outstanding mechanical properties and their bio-logical performances.This study focuses on improving the degradation rates and cytotoxicity of sintered Fe-Mn-C alloys produced using the powder metallurgy process.To evaluate the impact of different pow-der preparation methods on material properties,two types of powders were used:(1)MX,prepared by mixing Fe,Mn,and C powders for 1 h;and(2)MM,obtained by mechanically milling the same powders for 10 h.Four mixtures with varying proportions of MX and MM were prepared.Two groups of samples were produced:one entirely from MX(A0),and another containing MM at 25 wt.%(A25),50 wt.%(A50),and 75 wt.%(A75).All samples exhibited a complex microstructure comprising ferrite,martensite,and residual austenite.Degradation behavior assessment in Hanks’solution over 14 days showed that adding MM increased the degradation rate,from around 0.04 mmpy for A0 to 0.12 mmpy for A25.Notably,all samples showed similar cell viability,in the range of 83%-89%for 1%extract dilution,and were non-hemolytic,with a hemolysis percentage below 1%.
基金S.L.acknowledges funding from a Vanier Canada Graduate Scholarship(2017-2020).This work was partially supported by the Natural Science and Engineering Research Council of Canada(Discovery,Strategic,Collaborative Research and Development,and College-University-Industry Programs),the Quebec Ministry of Economy and Innovation,the Canadian Foundation for Innovation,and the FRQ-Sant'e through the support of the Research Center of the University Quebec Hospital,Regenerative Medicine Division.
文摘Twinning-induced plasticity(TWIP)steels are considered excellent materials for manufacturing products requiring extremely high mechanical properties for various applications including thin medical devices,such as biodegradable intravascular stents.It is also proven that the addition of Ag can guarantee an appropriate degradation while implanted in human body without affecting its bioactive properties.In order to develop an optimized manufacturing process for thin stents,the effect of Ag on the recrystallization behavior of TWIP steels needs to be elucidated.This is of major importance since manufacturing stents involves several intermediate recrystallization annealing treatments.In this work,the recrystallization mechanism of two Fe-Mn-C steels with and without Ag was thoroughly investigated by microstructural and mechanical analyses.It was observed that Ag promoted a finer microstructure with a different texture evolution,while the recrystallization kinetics resulted unaffected.The presence of Ag also reduced the effectiveness of the recrystallization treatment.This behavior was attributed to the presence of Ag-rich second phase particles,precipitation of carbides and to the preferential development of grains possessing a{111}orientation upon thermal treatment.The prominence of{111}grains can also give rise to premature twinning,explaining the role of Ag in reducing the ductility of TWIP steels already observed in other works.Furthermore,in vitro biological performances were unaffected by Ag.These findings could allow the design of efficient treatments for supporting the transformation of Fe-Mn-C steels alloyed with Ag into commercial products.
