摘要
Nb and Ti-13 Nb powders were used for improving the surface of Ti6Al4 V alloy.The deposition of the powders was carried out at various laser powers.The scanning electron microscopy（SEM）-EDS and optical microscopy were used for characterization.X-ray diffractometer（XRD） was used for analyzing the elemental composition and phase constituents.The hardness,wear and corrosion properties were achieved.The corrosion and the wear behaviours of the deposited layers were studied in a Hanks solution（simulated body fluid,SBF）.The microstructures of Nb coatings reveal the presence of orthorhombic,dendritic α″ and metastable β-Nb phases which produce uneven hardness with an average of HV 364.For Ti-13 Nb coatings,martensitic α′ and metastable β-Nb phases with an average hardness of HV 423 were observed.The resistance of wear on dry sliding of Ti-13 Nb coating is attributed to the increase in hardness.Experimental results indicate that deposition of Nb and Ti-13 Nb on Ti6Al4 V grossly reduces the mass fractions of Al and V in all coatings.In SBF,Nb reinforcement produces the best coating that reveals the best wear and corrosion resistances as compared with the substrate.Hence,this coating will perform best for orthopaedic implant material enhancement.
在不同功率下将Nb和Ti-13Nb粉末进行激光沉积,以改善Ti6Al4V合金的表面性能。采用扫描电镜(附带EDS能谱仪)和光学显微镜对样品进行表征,采用X射线衍射仪分析样品的元素组成及相组成,获得样品的硬度、磨损和耐腐蚀性能。在Hanks溶液(模拟体液)中研究沉积层的腐蚀和磨损行为。显微组织观察结果表明,沉积的Nb层为斜方晶系的树枝状α″和亚稳态β-Nb相,其硬度分布不均匀,平均硬度为HV 364;沉积的Ti-13Nb层为马氏体α′和亚稳态β-Nb相,其平均硬度为HV 423。干滑动摩擦条件下Ti-13Nb层的耐磨损性能归因于其硬度的增加。实验结果表明,在Ti6Al4V基体上沉积Nb和Ti-13Nb极大地降低了各层中Al和V的含量。在模拟体液中,与基体相比,Nb增强复合材料具有最好的耐磨损和耐腐蚀性能。因此,此复合材料将对改善整形外科植入材料性能发挥最佳作用。
基金
financially supported by the National Research Foundation of South Africa
The National Laser Centre,CSIR,Pretoria,South Africa,is appreciated for laser facility
the support from Tshwane University of Technology,South Africa
