In this work, the dry sliding wear behaviors of pure monolithic magnesium and magnesium–titanium dioxide (Mg–TiO₂) composites were studied using pin-on-disc tribometer against an oil-hardened nonshrinking die steel (OHNS) counter-disc with a normal load of 0.5–2kg and a sliding velocity of 1.5–2.5m⋅s−1 with the sliding distance and wear track diameter of 1500m and 90mm, respectively. The pin samples were characterized for their microstructural, nanomechanical and tribological properties such as wear rate, coefficient of friction and wear fractographs. Scanning electron microscopy (SEM) was used to analyze the worn-out surfaces of each pin sample in order to identify the different types of wear and wear mechanisms and the chemical constituents of each element were quantified by energy-dispersive spectroscopy. The influence of TiO₂ reinforcements on the nanomechanical behavior was studied by nanoindentation technique. As compared with pure Mg, the nanoindentation strengths of Mg–1.5TiO₂, Mg–2.5TiO₂ and Mg–5TiO₂ composites were found to increase by 11.9%, 22.2% and 35.8%, respectively, which was due to the addition of TiO₂ particles and also due to the good bonding at the interface of TiO₂ and magnesium particles. From the wear test results, a significant change in wear rate was observed with the change in normal load than that of sliding speed, whereas a significant change in coefficient of friction was noticed with the changes in both normal load and sliding velocity. The dominant wear mechanisms involved under the testing conditions were identified through plotting the contour maps and SEM fractographs. Also, from the fractographs it was noticed that delamination and plowing effect have been the significant wear mechanisms observed during low wear rate of samples, whereas melting, delamination and oxidation wear have been observed during high wear rate of pure Mg and its composites.

中文翻译：

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二氧化钛增强镁基复合材料干滑动磨损行为的研究

在这项工作中，纯整体式镁和镁-二氧化钛 (Mg-TiO ₂ ) 复合材料的干滑动磨损行为使用针盘式摩擦磨损计对油硬化非收缩模具钢 (OHNS) 配重盘进行了研究。正常负载 0.5–2kg 和 1.5–2.5 的滑动速度米⋅s-1滑动距离和磨损轨迹直径为 1500米和90毫米，分别。销钉样品的特征在于其微观结构、纳米机械和摩擦学特性，例如磨损率、摩擦系数和磨损断面图。扫描电子显微镜 (SEM) 用于分析每个销样品的磨损表面，以识别不同类型的磨损和磨损机制，并通过能量色散光谱法量化每种元素的化学成分。采用纳米压痕技术研究了TiO ₂增强材料对纳米力学行为的影响。与纯镁相比，Mg-1.5TiO ₂、Mg-2.5TiO ₂和Mg-5TiO _{2的纳米压痕强度}发现复合材料分别增加了 11.9%、22.2% 和 35.8%，这是由于 TiO _{2颗粒的添加以及在 TiO 2}界面处的良好结合。和镁颗粒。从磨损试验结果可以看出，磨损率随法向载荷的变化比滑动速度的变化显着，而摩擦系数随着法向载荷和滑动速度的变化而显着变化。通过绘制等高线图和 SEM 断口图确定了测试条件下涉及的主要磨损机制。此外，从断口形图中可以看出，在样品的低磨损率下观察到的显着磨损机制是分层和犁削效应，而在纯镁及其复合材料的高磨损率下观察到熔化、分层和氧化磨损。