离心铸造原位初生Si/Al_3Ni颗粒增强铝基复合材料

Microstructure and Properties of In-Situ Primary Si/Al_3Ni ParticlesReinforced Al Matrix Composites Fabricated by Centrifugal Casting

采用离心铸造制备原位初生Si和Al3Ni颗粒混合增强铝基复合材料的筒状铸件。通过光学显微镜(OM)、XRD、SEM、EDS以及洛氏硬度计等研究了复合材料的组织和性能。结果表明,所制备的复合材料铸件外层偏聚少量初生Si和大量Al3Ni颗粒,内层偏聚大量初生Si和少量Al3Ni颗粒,中间层没有增强颗粒。从铸件的外层到内层,增强颗粒的含量先降低后升高,复合材料的硬度也呈现出相应的变化规律。分析了离心场中多相流体的运动规律,发现复合材料中增强颗粒的分布与高重力系数G参数条件下初生Si和Al3Ni颗粒的密度以及它们的相互碰撞、粘结等作用有关。

In-situ primary Si and Al3Ni hybrid particles reinforced Al matrix composite tubes were fabricated by centrifugal casting.Microstructure and properties of the composites were investigated by OM（optical microscope）,XRD（X-ray diffraction）,SEM（scanning electron microscope） and Rockwell hardness tester.The results show that,the composite components produced possess microstructures accumulating lots of Al3Ni particles and a part of primary Si particles in the outer layer,and a little Al3Ni and lots of primary silicon particles in the inner layer,and no any primary particles in the middle layer.From outer layer to inner layer,the volume fraction of reinforcement particles are firstly decreased and then increased.The hardness of composites presents the same change rule as the volume fraction of particles.The movement rule of multiphase flow in the centrifugal field was analyzed.The distribution of reinforcement particles is relative to the density of primary Al3Ni and Si particles and collapse as well as adhesion each other under the high G parameter.