Gorgin Karaji Zahra, Hedayati Reza, Pouran Behdad, Apachitei Iulian, Zadpoor Amir A
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628, CD, Delft, The Netherlands; Department of Mechanical Engineering, Kermanshah University of Technology (KUT), 67156-85420, Kermanshah, Iran.
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628, CD, Delft, The Netherlands.
Mater Sci Eng C Mater Biol Appl. 2017 Jul 1;76:406-416. doi: 10.1016/j.msec.2017.03.079. Epub 2017 Mar 12.
Metallic porous biomaterials are recently attracting more attention thanks to the additive manufacturing techniques which help produce more complex structures as compared to conventional techniques. On the other hand, bio-functional surfaces on metallic biomaterials such as titanium and its alloys are necessary to enhance the biological interactions with the host tissue. This study discusses the effect of plasma electrolytic oxidation (PEO), as a surface modification technique to produce bio-functional layers, on the mechanical properties of additively manufactured Ti6Al4V scaffolds based on the cubic unit cell. For this purpose, the PEO process with two different oxidation times was applied on scaffolds with four different values of relative density. The effects of the PEO process were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), optical microscopy as well as static and dynamic (fatigue) mechanical testing under compression. SEM results indicated pore formation on the surface of the scaffolds after oxidation with a thickness of 4.85±0.36μm of the oxide layer after 2min and 9.04±2.27μm after 5min oxidation (based on optical images). The static test results showed the high effect of relative density of porous structure on its mechanical properties. However, oxidation did not influence most of the mechanical properties such as maximum stress, yield stress, plateau stress, and energy absorption, although its effect on the elastic modulus was considerable. Under fatigue loading, none of the scaffolds failed even after 10 loading cycles at 70% of their yield stress.
由于增材制造技术相比传统技术能够制造出更复杂的结构，金属多孔生物材料近来受到了更多关注。另一方面，诸如钛及其合金等金属生物材料上的生物功能表面对于增强与宿主组织的生物相互作用是必要的。本研究基于立方晶胞，探讨了作为一种用于制备生物功能层的表面改性技术的等离子体电解氧化（PEO）对增材制造的Ti6Al4V支架力学性能的影响。为此，对具有四种不同相对密度值的支架施加了两种不同氧化时间的PEO工艺。通过扫描电子显微镜（SEM）、能量色散X射线光谱（EDS）、光学显微镜以及压缩状态下的静态和动态（疲劳）力学测试研究了PEO工艺的效果。SEM结果表明，氧化后支架表面形成了孔隙，氧化2分钟后氧化层厚度为4.85±0.36μm，氧化5分钟后为9.04±2.27μm（基于光学图像）。静态测试结果表明多孔结构的相对密度对其力学性能有很大影响。然而，氧化对诸如最大应力、屈服应力、平台应力和能量吸收等大多数力学性能没有影响，尽管其对弹性模量的影响相当大。在疲劳载荷下，即使在以屈服应力的70%进行10次加载循环后，也没有支架失效。
