MAX相具有独特的层状晶体结构,不但具备常用铝基复合材料外加陶瓷颗粒的性能特征,同时具有可与石墨媲美的摩擦性能.本文以Al粉、Si粉和典型MAX相Ti3 SiC2为原料,采用冷压成型-无压烧结方法制备了Ti3 SiC2/Al-Si复合材料,并通过金相显微镜、X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)等分析手段,研究了烧结温度、Si元素含量对复合材料组织与性能的影响.研究表明:随着烧结温度从500℃提高到700℃,复合材料致密度先上升后下降,摩擦系数先降低后上升,硬度逐渐增大至最大值并基本保持稳定;随着Si质量分数从0增加到20.7%,复合材料的致密度逐渐降低,硬度逐渐增大,摩擦系数先降低后增大,晶粒尺寸随之下降,12.5%Si晶粒最为细小;烧结温度为650℃,Si元素质量分数为12.5%的铝基复合材料具有最低的摩擦系数0.18,相应的硬度为62 HV,致密度为92.12%.XRD物相和扫描电镜组织分析表明,复合材料的主要相组成为Al、Ti3 SiC2,及由界面反应产生的Al4 C3和Al的氧化产物Al2 O3.%MAX phase has a unique layered crystal structure, and possesses the excellent properties of the commonly used ceramic particulate reinforced aluminum composite, and good friction performance comparable to the graphite. Ti3SiC2/Al composites were fabricated by cold pressing and pressureless sintering using Ti3SiC2,Si and Al powers as raw materials. The effects of sintering temperature and Si content on the microstructure and properties of the composites were studied by means of optical microscopy, X-ray diffraction ( XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The results show that with increasing the sintering temperature from 500℃ to 700℃, the density of the composites firstly increases and then decreases, the friction coefficient firstly decreases and then increases, and the hardness gradually increases to the maximum and then remains almost unchanged. With increasing Si mass fraction from 0 to 20.7%, the density of the composites gradually decreases, the grain size decreases. The composite with 12.5%Si content possesses the smallest grain size. The aluminum matrix composites with 12.5%Si content sintered at 650℃ have the lowest coefficient of friction of 0.18, a hardness of 62 HV, a density of 92.12%. The main phases of the composites are Al, Ti3SiC2, Al2O3, Al4C3.
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