电子束熔融制造医用Ti6Al4V在人工模拟体液中耐腐蚀行为

目的研究电子束熔融技术（EBM）3D打印制备的医用Ti6Al4V不同打印截面在Hank's模拟人工体液中的电化学腐蚀行为。方法采用开路电位和动电位极化曲线方法研究了Ti6Al4V不同打印截面，分别记为EBM-XOY面（垂直于打印方向的钛合金截面）和EBM-YOZ面（平行于打印方向的钛合金截面），在Hank's模拟人工体液中的电化学腐蚀行为，利用SEM、XRD和金相显微镜分析了其表面形貌和物相组成及其腐蚀机理，并与传统医用锻造Ti6Al4V进行了对比研究。结果与传统医用锻造Ti6Al4V合金相比，EBM-YOZ面钛合金在Hank’s模拟人工体液中的开路电位、腐蚀电位和腐蚀电流与之相当，显示出与之接近的耐腐蚀性能；EBM-XOY面钛合金的耐腐蚀性能较EBM-XOZ面和传统锻造钛合金稍差，主要原因是EBM-XOY面的α+β相界面积大，α相含量较高，且被优先溶解，因此，耐腐蚀性能较差。结论电子束熔融制造的Ti6Al4V不同截面的耐腐蚀性能不同，EBM-YOZ面的耐腐蚀性能与传统医用锻造钛合金相当，EBM-XOY面的耐腐蚀性能稍差。

英文摘要:

Objective To study the corrosion behavior of medical Ti6Al4V alloys prepared by electron beam melting with EBM-XOY and EBM-YOZ cross-section that respect to the build direction in Hank’s solution. Methods Corrosion behavior and mechanism of the alloys was investigated in Hank's solution by means of open-circuit potential and potentiodynamic polarization techniques. The surface morphologies and phases were analyzed by SEM, XRD and optical micrographs. Commercially forged medical Ti6Al4V was also investigated to make a comparison. Results In comparison with forged Ti6Al4V, EBM-YOZ Ti6Al4V exhibited a good corrosion resistance with nearly the same open-circuit potential, corrosion potential and corrosion current. EBM-XOY Ti6Al4V exhibited inferior corrosion behavior to EBM-YOZ and forged Ti6Al4V alloys. This behavior can be attributed to more α phase and α+β phase interfaces, and the α phase appeared to be corroded to continued dissolution than the β phase. Conclusion The different cross-section of medical Ti6Al4V prepared by electron beam melting has the different corrosion resistance. EBM-YOZ section which is parallel to the build direction exhibited the similar corrosion resistance with commercially forged Ti6Al4V, while EBM-XOY section which is perpendicular to the build direction shown inferior corrosion behavior.

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