文章通过采用Gleeble1500热模拟机进行真空扩散连接试验,研究了氢对多孔Ti6Al4V合金扩散连接质量的影响,并应用光学显微镜、扫描电镜(Scanning electron microscope,SEM)及电子万能试验机对界面孔洞弥合率、界面组织形貌、抗弯强度和断...文章通过采用Gleeble1500热模拟机进行真空扩散连接试验,研究了氢对多孔Ti6Al4V合金扩散连接质量的影响,并应用光学显微镜、扫描电镜(Scanning electron microscope,SEM)及电子万能试验机对界面孔洞弥合率、界面组织形貌、抗弯强度和断口形貌进行分析。结果表明,真空扩散连接后的孔洞弥合率随着原始氢含量的增加而升高,但升高的趋势逐渐平缓;扩散连接后,原始氢含量较低的试样室温组织为α+片状(α+β),原始氢含量高的试样室温组织为条状α+等轴状(α+β);室温下,在一定的氢含量范围内,氢元素在多孔合金中以间隙固溶和氢化物状态存在,均起到了强化作用,使扩散连接后材料抗弯强度增加;随着剩余氢含量的增加,断口由韧性沿晶断裂逐渐转变为脆性沿晶断裂和解理型穿晶断裂两种断裂方式的混合,并且随着氢含量增加,穿晶解理断裂特征增多。展开更多
The advent of three-dimensional(3-D) printed technique provides great possibility in the fabrication of customized porous titanium(Ti) implant. However, the bioinert property of the printed Ti poses an outstanding pro...The advent of three-dimensional(3-D) printed technique provides great possibility in the fabrication of customized porous titanium(Ti) implant. However, the bioinert property of the printed Ti poses an outstanding problem. Hybrid micro-arc oxidation and hydrothermal(MAO–HT) treatment on porous metals is able to produce multi-scaled hierarchical orthopedic implant, showing great potential for surface modification of 3-D printed implant. In this study, cylindrical porous Ti6Al4V(Ti64) scaffolds with pore size of 640 μm, porosity of 73% were 3-D printed by electron beam melting process, and their surfaces were left untreated or treated by a combined MAO–HT procedure. In vitro bioactivity was tested by immersion in simulated body fluid for different time points. Then, 12 scaffolds in each group were implanted into the femoral condyles of New Zealand rabbit for 8 weeks. Osseointegration was evaluated by qualitative and quantitative histological analysis, and the bone ingrowth features were probed by sequential fluorescent labeling at 3 and 6 weeks post-surgery. Following the MAO–HT treatment, the porous Ti64 scaffold was endowed with multi-scaled micro/nano-topographies and high amounts of Ca P on its surface.The treated scaffold exhibited drastically enhanced apatite forming ability compared with the untreated one. In vivo test revealed significantly that a higher amount of bone ingrowth and bone implant contact at the treated scaffold. The 2 types of scaffolds had different patterns of bone ingrowth: the treated scaffold exhibited a pattern of contact osteogenesis, by which bone formed directly on the treated implant surface, whereas bone formed distal to the implant surface of the untreated scaffold. MAO–HT treatment can significantly enhance the in vitro apatite-inducing ability and in vivo osseointegration capacity of 3-D porous Ti64 scaffold and may provide as a viable approach for the fabrication of bioactive 3-D printed porous implant for orthopedic applications.展开更多
文摘文章通过采用Gleeble1500热模拟机进行真空扩散连接试验,研究了氢对多孔Ti6Al4V合金扩散连接质量的影响,并应用光学显微镜、扫描电镜(Scanning electron microscope,SEM)及电子万能试验机对界面孔洞弥合率、界面组织形貌、抗弯强度和断口形貌进行分析。结果表明,真空扩散连接后的孔洞弥合率随着原始氢含量的增加而升高,但升高的趋势逐渐平缓;扩散连接后,原始氢含量较低的试样室温组织为α+片状(α+β),原始氢含量高的试样室温组织为条状α+等轴状(α+β);室温下,在一定的氢含量范围内,氢元素在多孔合金中以间隙固溶和氢化物状态存在,均起到了强化作用,使扩散连接后材料抗弯强度增加;随着剩余氢含量的增加,断口由韧性沿晶断裂逐渐转变为脆性沿晶断裂和解理型穿晶断裂两种断裂方式的混合,并且随着氢含量增加,穿晶解理断裂特征增多。
基金Project supported by the National Natural Science Foundation of China(No.51775506)the Zhejiang Provincial Natural Science Foundation of China(No.LY18E050022)+2 种基金the Public Welfare Technology Application Research Project of Zhejiang Province(Nos.LGG19E050022 and 2017C33115)the Zhejiang Provincial Science&Technology Project for Medicine&Health(No.2018KY878)the Open Foundation of Zhejiang Provincial Top Key Discipline of Mechanical Engineering of Hangzhou Dianzi University,China
基金supported by FCT through the grants PD/BD/140202/2018,SFRH/BD/140191/2018 and SFRH/BD/128657/2017the projects PTDC/EMS-TEC/5422/2014 and NORTE-01-0145-FEDER-000018-HAMa BICo+1 种基金supported by FCT with the reference project UID/EEA/04436/2019the financial support through the M-ERA-NET/0001/2015 project(FCT)
基金the Beijing AKEC Medical Co.,LtdMedical Research Center of Peking University Third Hospitalsupported by the Project of Scientific and Technical Plan of Beijing(Nos.Z121100005312005 and Z141100002814008)
文摘The advent of three-dimensional(3-D) printed technique provides great possibility in the fabrication of customized porous titanium(Ti) implant. However, the bioinert property of the printed Ti poses an outstanding problem. Hybrid micro-arc oxidation and hydrothermal(MAO–HT) treatment on porous metals is able to produce multi-scaled hierarchical orthopedic implant, showing great potential for surface modification of 3-D printed implant. In this study, cylindrical porous Ti6Al4V(Ti64) scaffolds with pore size of 640 μm, porosity of 73% were 3-D printed by electron beam melting process, and their surfaces were left untreated or treated by a combined MAO–HT procedure. In vitro bioactivity was tested by immersion in simulated body fluid for different time points. Then, 12 scaffolds in each group were implanted into the femoral condyles of New Zealand rabbit for 8 weeks. Osseointegration was evaluated by qualitative and quantitative histological analysis, and the bone ingrowth features were probed by sequential fluorescent labeling at 3 and 6 weeks post-surgery. Following the MAO–HT treatment, the porous Ti64 scaffold was endowed with multi-scaled micro/nano-topographies and high amounts of Ca P on its surface.The treated scaffold exhibited drastically enhanced apatite forming ability compared with the untreated one. In vivo test revealed significantly that a higher amount of bone ingrowth and bone implant contact at the treated scaffold. The 2 types of scaffolds had different patterns of bone ingrowth: the treated scaffold exhibited a pattern of contact osteogenesis, by which bone formed directly on the treated implant surface, whereas bone formed distal to the implant surface of the untreated scaffold. MAO–HT treatment can significantly enhance the in vitro apatite-inducing ability and in vivo osseointegration capacity of 3-D porous Ti64 scaffold and may provide as a viable approach for the fabrication of bioactive 3-D printed porous implant for orthopedic applications.
