Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)h...Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys.This study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot extrusion.Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms.The extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant margin.Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the literature.Furthermore,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and filipodia.This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously.展开更多
In this study,the microstructures,mechanical properties,corrosion behaviors,and biocompatibility of extruded magnesium-zirconiumstrontium-holmium(Mg-Zr-Sr-Ho)alloys were comprehensively investigated.The effect of diff...In this study,the microstructures,mechanical properties,corrosion behaviors,and biocompatibility of extruded magnesium-zirconiumstrontium-holmium(Mg-Zr-Sr-Ho)alloys were comprehensively investigated.The effect of different concentrations of Ho on the microstructural characteristics,tensile and compressive properties,corrosion resistance,and biocompatibility were investigated.The microstructures of the extruded Mg-1Zr-0.5Sr-xHo(x=0.5,1.5,and 4 wt.%)alloys consisted ofα-Mg matrix,fineα-Zr particles,and intermetallic phase particles of Mg_(17)Sr_(2) and Ho_(2)Mg mainly distributed at the grain boundaries.Extensive{1012}tensile twins were observed in the partially recrystallized samples of Mg-1Zr-0.5Sr-0.5Ho and Mg-1Zr-0.5Sr-1.5Ho.Further addition of Ho to 4 wt.%resulted in a complete recrystallization due to activation of the particle stimulated nucleation around the Mg_(17)Sr_(2) particles.The evolution of a rare earth(RE)texture was observed with the Ho addition,which resulted in the weakened basal and prismatic textures.Furthermore,a drastic increase of 200%in tensile elongation and 89%in compressive strain was observed with Ho addition increased from 0.5 to 4 wt%,respectively.The tension-compression yield asymmetry was significantly decreased from 0.62 for Mg-1Zr-0.5Sr-0.5Ho to 0.98 for Mg-1Zr-0.5Sr-4Ho due to the weakening of textures.Corrosion analysis of the extruded Mg-Zr-Sr-Ho alloys revealed the presence of pitting corrosion.A minimum corrosion rate of 4.98 mm y^(−1) was observed in Mg-1Zr-0.5Sr-0.5Ho alloy.The enhanced corrosion resistance is observed due to the presence of Ho_(2)O_(3) in the surface film which reduced galvanic effect.The formation of a stabilized surface film due to the Ho_(2)O_(3) was confirmed through the electrical impedance spectroscopy and XPS analysis.An in vitro cytotoxicity assessment revealed good biocompatibility and cell adhesion in relation to SaOS2 cells.展开更多
In this study,extrusion was performed on Mg-Zr-Sr-Dy alloys for improving their mechanical,corrosion,and biocompatibility properties.Effects of extrusion and alloying elements on the microstructural characteristics,te...In this study,extrusion was performed on Mg-Zr-Sr-Dy alloys for improving their mechanical,corrosion,and biocompatibility properties.Effects of extrusion and alloying elements on the microstructural characteristics,tensile and compressive strengths,corrosion behavior,and biocompatibility were investigated.The Mg-Zr-Sr-Dy alloys were composed of an α-Mg matrix containing {10■2} extension twins and secondary phases of intermetallic compounds Mg_(17)Sr_(2) and Mg_(2)Dy.Evolution of basal and rare earth(RE) textures was observed in the extruded alloys and an increase in Dy content to 2 wt.% resulted in texture randomization and strengthening of the RE component,mainly due to particle-stimulated nucleation and a change from discontinuous dynamic recrystallization to continuous dynamic recrystallization,which also led to an improved tension-compression yield asymmetry of 0.87.Extrusion of the alloys significantly enhanced their tensile and compressive properties due to improved distribution of alloying elements and formation of textures.Corrosion rates tested by hydrogen evolution testing,potentiodynamic polarization,and electrical impedance spectroscopy showed similar trends for each composition,and the lowest corrosion rate of 3.37 mmy^(-1) was observed for the Mg-1Zr-0.5Sr-1Dy in the potentiodynamic polarization testing.Dy_(2)O_(3) was observed in the inner layers of the Mg(OH)_(2) protective films,whose protective efficacy was confirmed by charge-transfer and film resistances.A comparison among the minimum CRs observed in this study and previously studied as-cast Mg-Zr-Sr-Dy and extruded Mg-Zr-Sr alloys,demonstrates that both the extrusion process and addition of Dy in Mg-Zr-Sr improved the CR.Similarly,extruded Mg-Zr-Sr-Dy alloys showed improved cell viability and adhesion of human osteoblast-like SaOS2 cells due to increased corrosion resistance and enhanced Sr distribution within the Mg matrix.展开更多
Ti-Nb alloys have great potential in biomedical applications as bone-implant materials due to their low elastic modulus,superelasticity,high corrosion resistance,and good biocompatibility.However,the low yield strengt...Ti-Nb alloys have great potential in biomedical applications as bone-implant materials due to their low elastic modulus,superelasticity,high corrosion resistance,and good biocompatibility.However,the low yield strength and poor superelasticity of Ti-Nb alloys restrict their practical clinical applications.Here,we report the mechanical properties and superelasticity,corrosion behavior,and biocompatibility of a Ti-26 at.%Nb-1.2 vol.%TiC(Ti-26Nb-1.2TiC)shape memory composite(SMC)prepared by vacuum arc melting and hot rolling.The yield strength,critical stress for inducing martensitic transformation,and elongation of the Ti-26Nb-1.2TiC SMC and a Ti-26Nb alloy were 460 and 337 MPa,251 and 115 MPa,and 27.2%and 24.1%,respectively.The recovery rate of the SMC under 4%pre-strain reached 91.4%,which was 1.2 times that of the Ti-26Nb.Electrochemical tests in Hanks’solution revealed that the corrosion current density,passive current density,and corrosion rate of the SMC were lower than those of the Ti-26Nb.Both the Ti-26Nb alloy and Ti-26Nb-1.2TiC SMC showed good cell viability with grade 0 cytotoxicity in relation to MG-63 osteosarcoma cells.展开更多
Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical propertie...Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical properties of pure Zn greatly limit its clinical application. Here, we report on the microstructure, mechanical properties, friction and wear behavior, corrosion and degradation properties, hemocompatibility, and cytocompatibility of Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys under three different conditions of as-cast(AC),hot-rolling(HR), and hot-rolling plus cold-rolling(HR + CR). The HR + CR Zn–3 Cu–0.2 Ti exhibited the best set of comprehensive properties among all the alloy samples, with yield strength of 211.0 MPa, ultimate strength of 271.1 MPa, and elongation of 72.1 %. Immersion tests of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution for 3 months indicated that the AC samples showed the lowest degradation rate,followed by the HR samples, and then the HR + CR samples, while the HR + CR Zn–3 Cu exhibited the highest degradation rate of 23.9 m/a. Friction and wear testing of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution indicated that the AC samples showed the highest wear resistance, followed by the HR samples, and then the HR + CR samples, while the AC Zn–3 Cu–0.2 Ti showed the highest wear resistance.The diluted extracts of HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti at a concentration of ≤25 % exhibited noncytotoxicity. Furthermore, both the HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti exhibited effective antibacterial properties against S. aureus.展开更多
Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip syste...Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems,therefore exhibiting extremely low elongation and yield strength in its ascast condition,which restricts its clinical applications.In this study,as-cast Zn–xTi(titanium)(x=0.05,0.10,0.20,and 0.30 wt.%)binary alloys were hot-rolled and their microstructures,mechanical properties,wear resistance,and cytocompatibility were comprehensively investigated for orthopedic implant applications.The microstructures of both as-cast and hot-rolled Zn–xTi alloys consisted of anα-Zn matrix phase and a TiZn16 phase,while Zn–0.2 Ti and Zn–0.3 Ti exhibited a finerα-Zn phase due to the grainrefining effect of Ti.The hot-rolled Zn–0.2 Ti alloy exhibited the highest yield strength(144.5 MPa),ultimate strength(218.7 MPa),and elongation(54.2%)among all the Zn–x Ti alloys.The corrosion resistance of Zn–xTi alloys in Hanks’solution decreased with increasing addition of Ti,and the hot-rolled Zn–0.3 Ti alloy exhibited the highest corrosion rates of 432μm/y as measured by electrochemical testing and 57.9μm/y as measured by immersion testing.The as-cast Zn–xTi alloys showed lower wear losses than their hot-rolled counterparts.The extracts of hot-rolled Zn–x Ti alloys at concentrations of≤25%showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn–xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.展开更多
In this study,the microstructural evolution and mechanical properties of a newly developed Ti-40.7Zr-24.8Nb(TZN)alloy after different thermomechanical processes were examined.As-cast TZN alloy plates were solutiontrea...In this study,the microstructural evolution and mechanical properties of a newly developed Ti-40.7Zr-24.8Nb(TZN)alloy after different thermomechanical processes were examined.As-cast TZN alloy plates were solutiontreated at 890℃ for 1 h,after which the thickness of the alloy plates was reduced by cold rolling at reduction ratios of 20%,56%,76%,and 86%.Stress-induced α”formation,{332}<113>β mechanical twinning,and kink band formation were observed in the cold-rolled TZN alloy samples.In the TZN sample after cold rolling at the 86%reduction ratio plus a recrystallization annealing at 890℃ for 1 h,the deformation products of a stressinducedα”phase,{332}<113>β mechanical twinning,and kink bands disappeared,resulting in a fine,equiaxed singleβ phase.The alloy samples exhibited elongation at rupture ranging from 7%to 20%,Young's modulus ranging from 63 to 72 GPa and tensile strength ranging from 753 to 1158 MPa.The TZN alloy sample after cold rolling and recrystallization annealing showed a yield strength of 803 MPa,a tensile strength of 848 MPa,an elongation at rupture of 20%,and an elastic admissible strain of 1.22%,along with the most ductile fractures during tensile testing.展开更多
The strength of titanium scaffolds with the introduction of high porosity decreases dramatically and may become inadequate for load bearing in biomedical applications.To simultaneously meet the requirements of biocomp...The strength of titanium scaffolds with the introduction of high porosity decreases dramatically and may become inadequate for load bearing in biomedical applications.To simultaneously meet the requirements of biocompatibility,low elastic modulus and appropriate strength for orthopedic implant materials,it is highly desirable to develop new biocompatible titanium based materials with enhanced strength.In this study,we developed a niobium pentoxide(Nb2O5)reinforced titanium composite via powder metallurgy for biomedical applications.The strength of the Nb2O5 reinforced titanium composites(Ti-Nb2O5)is significantly higher than that of pure titanium.Cell culture results revealed that the Ti-Nb2O5 composite exhibits excellent biocompatibility and cell adhesion.Human osteoblast-like cells grew and spread healthily on the surface of the Ti-Nb2O5 composite.Our study demonstrated that Nb2O5 reinforced titanium composite is a promising implant material by virtue of its high mechanical strength and excellent biocompatibility.展开更多
基金the financial support provided by the Australian Research Council(ARC)through the Future Fellowship(FT160100252)the Discovery Project(DP170102557)for this research。
文摘Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys.This study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot extrusion.Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms.The extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant margin.Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the literature.Furthermore,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and filipodia.This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously.
基金the financial support for this research by the Australian Research Council(ARC)through the Future Fellowship(FT160100252)the Discovery Project(DP170102557)。
文摘In this study,the microstructures,mechanical properties,corrosion behaviors,and biocompatibility of extruded magnesium-zirconiumstrontium-holmium(Mg-Zr-Sr-Ho)alloys were comprehensively investigated.The effect of different concentrations of Ho on the microstructural characteristics,tensile and compressive properties,corrosion resistance,and biocompatibility were investigated.The microstructures of the extruded Mg-1Zr-0.5Sr-xHo(x=0.5,1.5,and 4 wt.%)alloys consisted ofα-Mg matrix,fineα-Zr particles,and intermetallic phase particles of Mg_(17)Sr_(2) and Ho_(2)Mg mainly distributed at the grain boundaries.Extensive{1012}tensile twins were observed in the partially recrystallized samples of Mg-1Zr-0.5Sr-0.5Ho and Mg-1Zr-0.5Sr-1.5Ho.Further addition of Ho to 4 wt.%resulted in a complete recrystallization due to activation of the particle stimulated nucleation around the Mg_(17)Sr_(2) particles.The evolution of a rare earth(RE)texture was observed with the Ho addition,which resulted in the weakened basal and prismatic textures.Furthermore,a drastic increase of 200%in tensile elongation and 89%in compressive strain was observed with Ho addition increased from 0.5 to 4 wt%,respectively.The tension-compression yield asymmetry was significantly decreased from 0.62 for Mg-1Zr-0.5Sr-0.5Ho to 0.98 for Mg-1Zr-0.5Sr-4Ho due to the weakening of textures.Corrosion analysis of the extruded Mg-Zr-Sr-Ho alloys revealed the presence of pitting corrosion.A minimum corrosion rate of 4.98 mm y^(−1) was observed in Mg-1Zr-0.5Sr-0.5Ho alloy.The enhanced corrosion resistance is observed due to the presence of Ho_(2)O_(3) in the surface film which reduced galvanic effect.The formation of a stabilized surface film due to the Ho_(2)O_(3) was confirmed through the electrical impedance spectroscopy and XPS analysis.An in vitro cytotoxicity assessment revealed good biocompatibility and cell adhesion in relation to SaOS2 cells.
基金the financial support for this research by the Australian Research Council (ARC) through the Future Fellowship (FT160100252)the Discovery Project (DP170102557)。
文摘In this study,extrusion was performed on Mg-Zr-Sr-Dy alloys for improving their mechanical,corrosion,and biocompatibility properties.Effects of extrusion and alloying elements on the microstructural characteristics,tensile and compressive strengths,corrosion behavior,and biocompatibility were investigated.The Mg-Zr-Sr-Dy alloys were composed of an α-Mg matrix containing {10■2} extension twins and secondary phases of intermetallic compounds Mg_(17)Sr_(2) and Mg_(2)Dy.Evolution of basal and rare earth(RE) textures was observed in the extruded alloys and an increase in Dy content to 2 wt.% resulted in texture randomization and strengthening of the RE component,mainly due to particle-stimulated nucleation and a change from discontinuous dynamic recrystallization to continuous dynamic recrystallization,which also led to an improved tension-compression yield asymmetry of 0.87.Extrusion of the alloys significantly enhanced their tensile and compressive properties due to improved distribution of alloying elements and formation of textures.Corrosion rates tested by hydrogen evolution testing,potentiodynamic polarization,and electrical impedance spectroscopy showed similar trends for each composition,and the lowest corrosion rate of 3.37 mmy^(-1) was observed for the Mg-1Zr-0.5Sr-1Dy in the potentiodynamic polarization testing.Dy_(2)O_(3) was observed in the inner layers of the Mg(OH)_(2) protective films,whose protective efficacy was confirmed by charge-transfer and film resistances.A comparison among the minimum CRs observed in this study and previously studied as-cast Mg-Zr-Sr-Dy and extruded Mg-Zr-Sr alloys,demonstrates that both the extrusion process and addition of Dy in Mg-Zr-Sr improved the CR.Similarly,extruded Mg-Zr-Sr-Dy alloys showed improved cell viability and adhesion of human osteoblast-like SaOS2 cells due to increased corrosion resistance and enhanced Sr distribution within the Mg matrix.
基金supported by the National Natural Science Foundation of China (Grant Nos.51971190 and 11872053)support for this research by the Australian Research Council (ARC)through the Discovery Project (No.DP210101862)Future Fellowship (No.FT160100252).
文摘Ti-Nb alloys have great potential in biomedical applications as bone-implant materials due to their low elastic modulus,superelasticity,high corrosion resistance,and good biocompatibility.However,the low yield strength and poor superelasticity of Ti-Nb alloys restrict their practical clinical applications.Here,we report the mechanical properties and superelasticity,corrosion behavior,and biocompatibility of a Ti-26 at.%Nb-1.2 vol.%TiC(Ti-26Nb-1.2TiC)shape memory composite(SMC)prepared by vacuum arc melting and hot rolling.The yield strength,critical stress for inducing martensitic transformation,and elongation of the Ti-26Nb-1.2TiC SMC and a Ti-26Nb alloy were 460 and 337 MPa,251 and 115 MPa,and 27.2%and 24.1%,respectively.The recovery rate of the SMC under 4%pre-strain reached 91.4%,which was 1.2 times that of the Ti-26Nb.Electrochemical tests in Hanks’solution revealed that the corrosion current density,passive current density,and corrosion rate of the SMC were lower than those of the Ti-26Nb.Both the Ti-26Nb alloy and Ti-26Nb-1.2TiC SMC showed good cell viability with grade 0 cytotoxicity in relation to MG-63 osteosarcoma cells.
基金supported financially by the Research Funds of the Wenzhou Science and Technology Bureau (Nos.ZG2019022 and 2018ZG008)support for this research by the Australian Research Council (ARC) through the Discovery Project (No.DP170102557)+1 种基金the Future Fellowship(No.FT160100252)support of the ARC Research Hub for Advanced Manufacturing of Medical Devices (No.IH150100024)。
文摘Zinc(Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical properties of pure Zn greatly limit its clinical application. Here, we report on the microstructure, mechanical properties, friction and wear behavior, corrosion and degradation properties, hemocompatibility, and cytocompatibility of Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys under three different conditions of as-cast(AC),hot-rolling(HR), and hot-rolling plus cold-rolling(HR + CR). The HR + CR Zn–3 Cu–0.2 Ti exhibited the best set of comprehensive properties among all the alloy samples, with yield strength of 211.0 MPa, ultimate strength of 271.1 MPa, and elongation of 72.1 %. Immersion tests of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution for 3 months indicated that the AC samples showed the lowest degradation rate,followed by the HR samples, and then the HR + CR samples, while the HR + CR Zn–3 Cu exhibited the highest degradation rate of 23.9 m/a. Friction and wear testing of the Zn–3 Cu and Zn–3 Cu–0.2 Ti alloys in Hanks’ solution indicated that the AC samples showed the highest wear resistance, followed by the HR samples, and then the HR + CR samples, while the AC Zn–3 Cu–0.2 Ti showed the highest wear resistance.The diluted extracts of HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti at a concentration of ≤25 % exhibited noncytotoxicity. Furthermore, both the HR + CR Zn–3 Cu and Zn–3 Cu–0.2 Ti exhibited effective antibacterial properties against S. aureus.
基金the Wenzhou Science and Technology Bureau through the project ZG2019022 and 2018ZG008financial support for this research by the Australian Research Council(ARC)through the Discovery Project DP170102557+1 种基金Future Fellowship FT160100252the support of the ARC Research Hub for Advanced Manufacturing of Medical Devices(IH150100024)。
文摘Zinc(Zn)and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants.Nevertheless,pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems,therefore exhibiting extremely low elongation and yield strength in its ascast condition,which restricts its clinical applications.In this study,as-cast Zn–xTi(titanium)(x=0.05,0.10,0.20,and 0.30 wt.%)binary alloys were hot-rolled and their microstructures,mechanical properties,wear resistance,and cytocompatibility were comprehensively investigated for orthopedic implant applications.The microstructures of both as-cast and hot-rolled Zn–xTi alloys consisted of anα-Zn matrix phase and a TiZn16 phase,while Zn–0.2 Ti and Zn–0.3 Ti exhibited a finerα-Zn phase due to the grainrefining effect of Ti.The hot-rolled Zn–0.2 Ti alloy exhibited the highest yield strength(144.5 MPa),ultimate strength(218.7 MPa),and elongation(54.2%)among all the Zn–x Ti alloys.The corrosion resistance of Zn–xTi alloys in Hanks’solution decreased with increasing addition of Ti,and the hot-rolled Zn–0.3 Ti alloy exhibited the highest corrosion rates of 432μm/y as measured by electrochemical testing and 57.9μm/y as measured by immersion testing.The as-cast Zn–xTi alloys showed lower wear losses than their hot-rolled counterparts.The extracts of hot-rolled Zn–x Ti alloys at concentrations of≤25%showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn–xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.
基金the financial support for this research by the National Health and Medical Research Council(NHMRC),Australia,through grant GNT1087290and the Australian Research Council(ARC)through the discovery grant DP170102557+1 种基金YL is also supported through an ARC Future Fellowship(FT160100252)the support for this research by Hunan Provincial Natural Science Foundation of China through the Grant 2016JC2005.
文摘In this study,the microstructural evolution and mechanical properties of a newly developed Ti-40.7Zr-24.8Nb(TZN)alloy after different thermomechanical processes were examined.As-cast TZN alloy plates were solutiontreated at 890℃ for 1 h,after which the thickness of the alloy plates was reduced by cold rolling at reduction ratios of 20%,56%,76%,and 86%.Stress-induced α”formation,{332}<113>β mechanical twinning,and kink band formation were observed in the cold-rolled TZN alloy samples.In the TZN sample after cold rolling at the 86%reduction ratio plus a recrystallization annealing at 890℃ for 1 h,the deformation products of a stressinducedα”phase,{332}<113>β mechanical twinning,and kink bands disappeared,resulting in a fine,equiaxed singleβ phase.The alloy samples exhibited elongation at rupture ranging from 7%to 20%,Young's modulus ranging from 63 to 72 GPa and tensile strength ranging from 753 to 1158 MPa.The TZN alloy sample after cold rolling and recrystallization annealing showed a yield strength of 803 MPa,a tensile strength of 848 MPa,an elongation at rupture of 20%,and an elastic admissible strain of 1.22%,along with the most ductile fractures during tensile testing.
基金This research is financially supported by the National Health and Medical Research Council(NHMRC)through GNT1087290.
文摘The strength of titanium scaffolds with the introduction of high porosity decreases dramatically and may become inadequate for load bearing in biomedical applications.To simultaneously meet the requirements of biocompatibility,low elastic modulus and appropriate strength for orthopedic implant materials,it is highly desirable to develop new biocompatible titanium based materials with enhanced strength.In this study,we developed a niobium pentoxide(Nb2O5)reinforced titanium composite via powder metallurgy for biomedical applications.The strength of the Nb2O5 reinforced titanium composites(Ti-Nb2O5)is significantly higher than that of pure titanium.Cell culture results revealed that the Ti-Nb2O5 composite exhibits excellent biocompatibility and cell adhesion.Human osteoblast-like cells grew and spread healthily on the surface of the Ti-Nb2O5 composite.Our study demonstrated that Nb2O5 reinforced titanium composite is a promising implant material by virtue of its high mechanical strength and excellent biocompatibility.
