Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran, Iran; Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran, Iran.
J Mech Behav Biomed Mater. 2018 Mar;79:246-253. doi: 10.1016/j.jmbbm.2018.01.007. Epub 2018 Jan 10.
In this study, alumina-reinforced poly(methyl methacrylate) nanocomposites (PMMA/AlO) containing up to 20vol% nanoparticles with an average diameter of 50nm were prepared by friction stir processing. The effects of nanoparticle volume fraction on the microstructural features and mechanical properties of PMMA were studied. It is shown that by using a frustum pin tool and employing an appropriate processing condition, i.e. a rotational speed of 1600rpm/min and transverse velocity of 120mm/min, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared. Mechanical evaluations including tensile, flexural, hardness and impact tests indicate that the strength and toughness of the material gradually increases with the nanoparticle concentration and reach to a flexural strength of 129MPa, hardness of 101 Shore D, and impact energy 2kJ/m for the nanocomposite containing 20vol% alumina. These values are about 10% and 20% better than untreated and FSP-treated PMMA (without alumina addition). Fractographic studies indicate typical brittle features with crack deflection around the nanoparticles. More interestingly, the sliding wear rate in a pin-on-disk configuration and the friction coefficient are reduced up to 50% by addition of alumina nanoparticles. The worn surfaces exhibit typical sliding and ploughing features.
在这项研究中，通过摩擦搅拌处理制备了氧化铝增强聚甲基丙烯酸甲酯纳米复合材料（PMMA/AlO），其中纳米粒子的体积分数高达 20vol%，平均直径为 50nm。研究了纳米粒子体积分数对 PMMA 的微观结构特征和力学性能的影响。结果表明，使用截顶销工具并采用适当的加工条件，即转速为 1600rpm/min 和横向速度为 120mm/min，可以成功制备无缺陷的纳米复合材料，纳米粒子分布均匀。拉伸、弯曲、硬度和冲击试验等力学性能评估表明，材料的强度和韧性随着纳米粒子浓度的增加而逐渐提高，含有 20vol%氧化铝的纳米复合材料的弯曲强度达到 129MPa，硬度达到 101Shore D，冲击能达到 2kJ/m。这些值比未经处理和 FSP 处理的 PMMA（未添加氧化铝）分别提高了约 10%和 20%。断口形貌分析表明，典型的脆性特征是裂纹在纳米粒子周围发生偏转。更有趣的是，通过添加氧化铝纳米粒子，滑动磨损率和摩擦系数在销盘配置中降低了高达 50%。磨损表面呈现出典型的滑动和犁沟特征。
