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首页> 外文期刊>Journal of biomedical materials research. Part B, Applied biomaterials. >Defect initiation at subsurface grain boundary as a precursor of delamination in ultrahigh molecular weight polyethylene
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Defect initiation at subsurface grain boundary as a precursor of delamination in ultrahigh molecular weight polyethylene

机译：作为超高分子量聚乙烯中脱层的前兆，在表面晶界处引发缺陷

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摘要

In order to examine the initiation mechanism of delamination in ultrahigh molecular weight polyethylene (UHMWPE) knee components, a bi-directional sliding fatigue test was performed for three types of UHMWPE specimens: nonirradiated, gamma-irradiated (25 kGy) and gamma-irradiated (25 kGy) with 0.1 percent vitamin E added. Sliding surfaces of post-tested UHMWPE specimens were observed using an optical microscope and a scanning electron microscope. Also, surface roughness was measured at the sliding surfaces of UHMWPE specimens. Delamination was observed only in gamma-irradiated specimens. A networked structure of surface asperity that resembled grain boundary was observed prior to delamination in gamma-irradiated specimens. Surface roughness in the gamma-irradiated specimens, higher than in any other specimen, showed a rapid increase prior to delamination. Detailed observation using an optical microscope and a scanning electron microscope showed microscopic crack initiation along subsurface grain boundaries in gamma-irradiated specimens. These results suggest that subsurface crack initiation is a precursor of delamination and is accelerated by oxidative degradation due to gamma irradiation. Of the three types of specimens, UHMWPE with vitamin E added showed the lowest surface roughness values at all measuring points. The addition of vitamin F is effective in improving wear resistance and fatigue performance of UHMWPE.
机译：为了检查超高分子量聚乙烯（UHMWPE）膝关节组件分层的引发机理，对三种类型的UHMWPE样品进行了双向滑动疲劳测试：未辐照，γ辐照（25 kGy）和γ辐照（ 25 kGy），添加0.1％的维生素E。使用光学显微镜和扫描电子显微镜观察后测试的UHMWPE标本的滑动表面。而且，在UHMWPE样品的滑动表面上测量了表面粗糙度。仅在伽马射线辐照的样品中观察到分层。在γ辐照的样品分层之前，观察到类似于晶粒边界的表面粗糙结构的网络结构。 γ辐照样品的表面粗糙度高于任何其他样品，在分层前显示出快速增加。使用光学显微镜和扫描电子显微镜进行的详细观察显示，在γ射线辐照的样品中，沿表面下晶界出现了微观裂纹。这些结果表明，地下裂纹的萌生是分层的先兆，并且由于伽马辐照引起的氧化降解而加速了。在这三种类型的样品中，添加了维生素E的UHMWPE在所有测量点均显示出最低的表面粗糙度值。维生素F的添加有效地改善了UHMWPE的耐磨性和疲劳性能。

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