汽缸套自生颗粒增强Al-Si-Mg复合材料的制备与台架实验研究

Preparation of Al-Si-Mg Composites Reinforced by in Situ Particles Used for Cylinder Liner and Research on Bench Test

观察并研究离心铸造自生颗粒增强Al-Si-Mg复合材料600 cc发动机铝合金缸套铸件沿径向方向的微观组织特征,检测铸件的硬度及耐磨性能;对铝合金缸套内表面腐蚀处理后进行台架实验。结果表明：Al-Si-Mg复合材料铸件内层偏聚了大量的自生初晶Si/Mg2Si颗粒,体积分数达27.6%,初晶颗粒体积分数较大的区域其硬度值也较高,铝合金缸套内层增强层的体积磨损量低于摩托车用铸铁缸套;低压铸造时,需在铝合金缸体内孔装填耐火棉,以保证铸件充型完整且不发生跑火现象,铸造成型缸体与缸套之间获得良好的冶金结合效果;台架实验测得600 cc铝合金缸体发动机的输出功率最大达22.66 k W,转矩最大达44.37 N·m,达到设计要求。

The centrifugal casting process was adopted to fabricate Al-Si-Mg composite reinforced with in situ particles which was used to produce 600 cc engine cylinder. The micro-structures along the radial direction of the casting were studied,and the hardness and wear resistance of the cast were examined. The inner layer of the Al-Si-Mg cylinder liner was corroded and a bench test was carried out. It is found that a large number of primary Si/Mg2Si particles are segregated in the inner layer of Al-Si-Mg composite casting. The maximum particle volume fraction in the inner layer is up to 27.6%. The hardness value of the region which has more primary particles is higher as well. The volume wear loss of inner layer of Al-Si-Mg cylinder liner is lower than that of a cast iron cylinder used for motorbike. During low pressure casting, the inner hole of the aluminum alloy cylinder body needs to be filled with refractory cotton to ensure the completion of the cast and nonoccurrence of the running-out phenomenon of Al melt. The low pressure casting cylinder gets good metallurgical bonding effect. The measured maximum engine power and engine torque of the 600 cc water-cooled engine reach 22.66 k W and 44.37 N·m, respectively tested by the bench test, which meets the design requirements.