Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of componen...Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder feedstock.This work investigated the microstructure,phase composition,melt pool morphology,and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder mixture.The samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in theα/βmatrix,resulting from the unstable melt pool during the melting of the powder mixture.By contrast,parts produced from prealloyed powder display a homogeneous microstructure withβandαphases,owing to the full melting of prealloyed powder,therefore,a more stable melt pool to achieve a homogeneous microstructure.The Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility(about 10 times that of the counterparts using mixed powder),attributed to the high homogeneity in microstructure and chemical composition,strong interface bonding,relatively low oxygen content,and the existence of a large amount ofβphase.This work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.展开更多
Although using elemental powder mixtures may provide broad alloy selection at low cost for selective laser melting(SLM), there is still a concern on the resultant microstructural and chemical homogeneity of the produc...Although using elemental powder mixtures may provide broad alloy selection at low cost for selective laser melting(SLM), there is still a concern on the resultant microstructural and chemical homogeneity of the produced parts. Hence, this work investigates the microstructure and mechanical properties of a SLM-produced Ti-35 Nb composite(in wt%) using elemental powder. The microstructural characteristics including ? phase, undissolved Nb particles and chemical homogeneity were detailed investigated.Nanoindentation revealed the presence of relatively soft undissolved Nb particles and weak interface bonding around Nb-rich regions in as-SLMed samples. Solid-solution treatment can not only improve chemical homogeneity but also enhance bonding through grain boundary strengthening, resulting in43 % increase in tensile elongation for the heat-treated Ti-35 Nb compared to the as-SLMed counterpart. The analyses of tensile fractures and shear bands further confirmed the correlation between the different phases and the ductility of Ti-35 Nb. In particular, the weak bonding between undissolved Nb and the matrix in the as-SLMed sample reduces its ductility while the ? grains in solid-solution treated Ti-Nb alloy can induce a relatively stable plastic flow therefore better ductility. This work sheds insight into the understanding of homogenization of microstructure and phases of SLM-produced alloys from an elemental powder mixture.展开更多
Binary titanium–niobium(Ti–Nb)alloys have recently been attracted due to low Young’s moduli and non-toxic properties.This study explores the influence of low Nb content(0–25 wt%)on the comprehensive parameters of ...Binary titanium–niobium(Ti–Nb)alloys have recently been attracted due to low Young’s moduli and non-toxic properties.This study explores the influence of low Nb content(0–25 wt%)on the comprehensive parameters of tensile stress–strain relationships(ultimate strength(rUTS),yield strength(r0.2)and elastic modulus(E)),surfaces properties(Vickers microhardness,surface roughness(Ra),water contact angle(WCA),X-ray diffraction(XRD)and scanning electron microscopy(SEM)),corrosion resistance(in artificial saliva and lactic acid)and biological properties(cytotoxicity and alkaline phosphatase activity of MC3T3-E1 pre-osteoblasts)of Ti–xNb alloys(x紏5,10,15,20 and 25 wt%),with using commercially pure grade 2 titanium(cp-Ti)as control.XRD results shown that all the Ti–xNb alloys comprised atb Ti alloy phases,such that the b phase increased correspondingly with the increased amount of Nb in the alloy,as well as the reduction of E(69–87 GPa).Except Ti–5Nb,all other Ti–xNb alloys showed a significantly higher hardness,increased rUTS and r0.2,and decreased WCA compared with cp-Ti.No corrosion was detected on Ti–xNb alloys and cp-Ti in artificial saliva and lactic acid solutions.The cytotoxicity of Ti–xNb alloys was comparable to that of cp-Ti in MC3T3-E1 pre-osteoblasts without interference from differentiation behaviour,but the proliferation rate of the Ti–5Nb alloy was lower than other groups.In overall,binary Ti–(10–25 wt%)Nb alloys are promising candidate for orthopaedic and dental implants due to their improved mechanical properties and comparable biological performance,while Ti–5Nb should be used with caution.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
[目的]通过体内实验的方法对新型β型钛合金(Ti-Nb-Zr)骨折内固定材料的生物相容性进行评价。[方法](1)改良的鼠气囊模型(the air pouch model):健康成年SD大鼠24只,皮下充气造模后将钛铌铣β型钛合金(Ti-Nb-Zr)颗粒混悬液注入气囊,收...[目的]通过体内实验的方法对新型β型钛合金(Ti-Nb-Zr)骨折内固定材料的生物相容性进行评价。[方法](1)改良的鼠气囊模型(the air pouch model):健康成年SD大鼠24只,皮下充气造模后将钛铌铣β型钛合金(Ti-Nb-Zr)颗粒混悬液注入气囊,收集囊内液体采用ELISA方法测定IL-6和TNF-α,用囊壁组织学切片进行炎症细胞反应分级和囊壁厚度测量,并与传统的钛铅钒合金(Ti-6Al-4V)进行比较。(2)接骨板植入模型:将Ti-Nb-Zr做成接骨板固定在兔的胫骨上,于手术后4、8、12、24、36周分别观察接骨板周围的纤维膜形成情况和Ti-Nb-Zr-骨界面骨结合情况,并与不锈钢接骨板比较。[结果](1)Ti-6Al-4V、Ti-Nb-Zr两种颗粒注入气囊48h后都能引起TNF-α分泌量显著升高(P<0·05),两组比较,Ti-6Al-4V组明显高于Ti-Nb-Zr组(P<0·05)。两种材料均不能引起IL-6分泌的显著增加(P>0·05)。Ti-Nb-Zr组气囊囊壁厚度明显小于Ti-6Al-4V组(P<0·001)。(2)Ti-Nb-Zr接骨板周围软组织反应与不锈钢相近。植入后4周,新生骨痂开始覆盖Ti-Nb-Zr接骨板的两侧,8周时骨痂甚至部分覆盖接骨板和螺钉的表面形成"骨盖板"现象。12周时,骨与Ti-Nb-Zr接骨板的界面为直接接触,中间无软组织间隔。螺钉与骨也能形成较为牢固的钉-骨直接接触。[结论]低弹性模量Ti-Nb-Zrβ钛合金具有优良的体内组织相容性,是一种有前途的骨折内固定材料。展开更多
基金the support of the Australian Government Research Training Program Scholarship and Forrest Research Foundation Ph D scholarshipthe fnancial support provided by the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials(No.2021GXYSOF03)and the facilitiesthe scientifc and technical assistance of the Australian Microscopy&Microanalysis Research Facility at the Centre for Microscopy,Characterisation&Analysis,The University of Western Australia,a facility funded by the University,State and Commonwealth Governments。
文摘Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder feedstock.This work investigated the microstructure,phase composition,melt pool morphology,and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder mixture.The samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in theα/βmatrix,resulting from the unstable melt pool during the melting of the powder mixture.By contrast,parts produced from prealloyed powder display a homogeneous microstructure withβandαphases,owing to the full melting of prealloyed powder,therefore,a more stable melt pool to achieve a homogeneous microstructure.The Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility(about 10 times that of the counterparts using mixed powder),attributed to the high homogeneity in microstructure and chemical composition,strong interface bonding,relatively low oxygen content,and the existence of a large amount ofβphase.This work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.
基金support of the ECU Postgraduate Research AwardForrest Research Foundation Ph D Scholarship+1 种基金the Australian Government Research Training Program Scholarship(ECU)the facilities,and the scientific and technical assistance of the Australian Microscopy&Microanalysis Research Facility at the Centre for Microscopy,Characterisation&Analysis,The University of Western Australia,a facility funded by the University,State and Commonwealth Governments。
文摘Although using elemental powder mixtures may provide broad alloy selection at low cost for selective laser melting(SLM), there is still a concern on the resultant microstructural and chemical homogeneity of the produced parts. Hence, this work investigates the microstructure and mechanical properties of a SLM-produced Ti-35 Nb composite(in wt%) using elemental powder. The microstructural characteristics including ? phase, undissolved Nb particles and chemical homogeneity were detailed investigated.Nanoindentation revealed the presence of relatively soft undissolved Nb particles and weak interface bonding around Nb-rich regions in as-SLMed samples. Solid-solution treatment can not only improve chemical homogeneity but also enhance bonding through grain boundary strengthening, resulting in43 % increase in tensile elongation for the heat-treated Ti-35 Nb compared to the as-SLMed counterpart. The analyses of tensile fractures and shear bands further confirmed the correlation between the different phases and the ductility of Ti-35 Nb. In particular, the weak bonding between undissolved Nb and the matrix in the as-SLMed sample reduces its ductility while the ? grains in solid-solution treated Ti-Nb alloy can induce a relatively stable plastic flow therefore better ductility. This work sheds insight into the understanding of homogenization of microstructure and phases of SLM-produced alloys from an elemental powder mixture.
基金The study was partially supported by the National Natural Science Foundation of China(NSFC)(grant number 81771126).
文摘Binary titanium–niobium(Ti–Nb)alloys have recently been attracted due to low Young’s moduli and non-toxic properties.This study explores the influence of low Nb content(0–25 wt%)on the comprehensive parameters of tensile stress–strain relationships(ultimate strength(rUTS),yield strength(r0.2)and elastic modulus(E)),surfaces properties(Vickers microhardness,surface roughness(Ra),water contact angle(WCA),X-ray diffraction(XRD)and scanning electron microscopy(SEM)),corrosion resistance(in artificial saliva and lactic acid)and biological properties(cytotoxicity and alkaline phosphatase activity of MC3T3-E1 pre-osteoblasts)of Ti–xNb alloys(x紏5,10,15,20 and 25 wt%),with using commercially pure grade 2 titanium(cp-Ti)as control.XRD results shown that all the Ti–xNb alloys comprised atb Ti alloy phases,such that the b phase increased correspondingly with the increased amount of Nb in the alloy,as well as the reduction of E(69–87 GPa).Except Ti–5Nb,all other Ti–xNb alloys showed a significantly higher hardness,increased rUTS and r0.2,and decreased WCA compared with cp-Ti.No corrosion was detected on Ti–xNb alloys and cp-Ti in artificial saliva and lactic acid solutions.The cytotoxicity of Ti–xNb alloys was comparable to that of cp-Ti in MC3T3-E1 pre-osteoblasts without interference from differentiation behaviour,but the proliferation rate of the Ti–5Nb alloy was lower than other groups.In overall,binary Ti–(10–25 wt%)Nb alloys are promising candidate for orthopaedic and dental implants due to their improved mechanical properties and comparable biological performance,while Ti–5Nb should be used with caution.
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.
文摘[目的]通过体内实验的方法对新型β型钛合金(Ti-Nb-Zr)骨折内固定材料的生物相容性进行评价。[方法](1)改良的鼠气囊模型(the air pouch model):健康成年SD大鼠24只,皮下充气造模后将钛铌铣β型钛合金(Ti-Nb-Zr)颗粒混悬液注入气囊,收集囊内液体采用ELISA方法测定IL-6和TNF-α,用囊壁组织学切片进行炎症细胞反应分级和囊壁厚度测量,并与传统的钛铅钒合金(Ti-6Al-4V)进行比较。(2)接骨板植入模型:将Ti-Nb-Zr做成接骨板固定在兔的胫骨上,于手术后4、8、12、24、36周分别观察接骨板周围的纤维膜形成情况和Ti-Nb-Zr-骨界面骨结合情况,并与不锈钢接骨板比较。[结果](1)Ti-6Al-4V、Ti-Nb-Zr两种颗粒注入气囊48h后都能引起TNF-α分泌量显著升高(P<0·05),两组比较,Ti-6Al-4V组明显高于Ti-Nb-Zr组(P<0·05)。两种材料均不能引起IL-6分泌的显著增加(P>0·05)。Ti-Nb-Zr组气囊囊壁厚度明显小于Ti-6Al-4V组(P<0·001)。(2)Ti-Nb-Zr接骨板周围软组织反应与不锈钢相近。植入后4周,新生骨痂开始覆盖Ti-Nb-Zr接骨板的两侧,8周时骨痂甚至部分覆盖接骨板和螺钉的表面形成"骨盖板"现象。12周时,骨与Ti-Nb-Zr接骨板的界面为直接接触,中间无软组织间隔。螺钉与骨也能形成较为牢固的钉-骨直接接触。[结论]低弹性模量Ti-Nb-Zrβ钛合金具有优良的体内组织相容性,是一种有前途的骨折内固定材料。
