2024铝合金微弧氧化/TiC复合膜的制备及耐磨性能

在含有TiC微粒的硅酸盐体系电解液中对2024铝合金进行微弧氧化处理,制备含有TiC成分的复合陶瓷膜。利用SEM、EDS、XRD观察分析复合陶瓷膜的微观形貌、膜层中主要成分沿截面方向的分布及膜层的相结构,用纳米压痕硬度仪、激光共聚焦显微镜、摩擦磨损试验机测量复合陶瓷膜的硬度、表面粗糙度及摩擦系数。观察磨痕形貌,采用激光共聚焦显微镜测量磨痕体积,评估磨损率。结果表明:与不含TiC微粒的电解液中制备的微弧氧化膜相比,复合陶瓷膜的硬度更高、摩擦系数更小、磨损率更低,复合陶瓷膜的磨损率仅为微弧氧化膜的1/12,耐磨性更好。

Microstructure and phase forming process of Al-3Ti-0.2C-1RE grain refiner

An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method.The microstructure was investigated by optical microscopy(OM),scanning electron microscopy(SEM) equipped with energy-dispersive spectrometry(EDS) and X-ray diffraction(XRD).The results show that the Al-3Ti-0.2C-1RE grain refiner is composed of α-Al,TiAl3,TiC and Ti2 Al20 Ce phases.Compared with Al-3Ti-0.2C refiner,the morphology of TiAl3 phase is changed and Ti2 Al20 Ce phases form with the addition of RE.Accordingly,the refining performance is improved.The phase forming process of the refiner is as follows: Blocky Ti2 Al20 Ce and fine blocky TiAl3 form in the melt at the initial stage of reaction,then the fine blocky TiAl3 gradually disappears,and the blocky Ti2 Al20 Ce grows bigger with the increase of holding time.The predominant mechanism to synthesize TiC particles is the reaction between high concentration of solute Ti atoms and graphite particles.