Magnesium-based implants are subjected to complicated stresses during implantation in the human body. The stress effects on corrosion of magnesium (Mg) in vitro were investigated in previous studies, whereas in this study, the corrosion behaviors of high-purity (HP) Mg under stress were comparatively studied in vitro in Hank's solution and in vivo in the subcutaneous environment of rats. Loading devices were designed to apply compressive stress (15.1 ± 0.5 MPa) and tensile stress (13.2 ± 0.2 MPa) on HP Mg specimens both in vitro and in vivo. Corrosion rates of HP Mg were characterized by mass and volume losses. It was shown that the applied compressive stress had no effect on in vitro corrosion behaviors and the applied tensile stress accelerated the in vitro corrosion, thereby causing severe pitting corrosions and stress corrosion cracking (SCC). However, there was no significant change for corrosion behaviors in vivo under neither compressive stress nor tensile stress. Severe pitting corrosion and SCC did not occur in vivo. Histological evaluation revealed that a fibrotic capsule induced by foreign body reaction was formed on the corrosion surfaces of HP Mg in the subcutaneous environment. It was proposed that the fibrotic capsule suppressed the effects of stress in vivo by protecting the corrosion surfaces. These results provided new insights into understanding the stress effects on the corrosion of Mg both in vitro and in vivo. STATEMENT OF SIGNIFICANCE: Mg and its alloys have shown potential as biodegradable metallic materials. During implantation, Mg is subjected to various mechanical environments in the human body. It is necessary to have a clear understanding of different effects of stress on Mg corrosion. However, few studies were performed in vivo. It is important to analyze the effect of quantitative stress on Mg corrosion in vivo. Therefore, in this study, quantitative stresses were applied on Mg both in vitro and in vivo. The effects of stress on in vitro and in vivo corrosions of Mg were investigated and compared.

中文翻译：

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应力对体内外高纯度镁腐蚀的影响。

镁基植入物在人体植入过程中会承受复杂的应力。在先前的研究中研究了应力对镁（Mg）体外腐蚀的影响，而在这项研究中，在Hank溶液中体外和体内在皮下对高纯度（HP）Mg在应力下的腐蚀行为进行了比较研究。大鼠的环境。设计了加载装置，可在体内和体外对HP Mg标本施加压应力（15.1±0.5 MPa）和拉应力（13.2±0.2 MPa）。HP Mg的腐蚀速率以质量和体积损失为特征。结果表明，施加的压缩应力对体外腐蚀行为没有影响，施加的拉伸应力促进了体外腐蚀，从而导致严重的点蚀和应力腐蚀开裂（SCC）。但是，在压缩应力和拉伸应力下，体内的腐蚀行为都没有显着变化。在体内未发生严重的点蚀和SCC。组织学评估表明，在皮下环境中，HP Mg的腐蚀表面形成了由异物反应引起的纤维化囊。有人提出，纤维化囊通过保护腐蚀表面来抑制体内应力的作用。这些结果为了解应力在体外和体内对镁腐蚀的影响提供了新的见解。意义声明：镁及其合金已显示出可生物降解的金属材料的潜力。在植入过程中，镁在人体中经受各种机械环境。必须清楚地了解应力对镁腐蚀的不同影响。但是，很少进行体内研究。重要的是要分析定量应力对体内镁腐蚀的影响。因此，在这项研究中，在体内和体外都对镁施加了定量应力。研究和比较了应力对镁体外和体内腐蚀的影响。