Bi对Al-20Si合金微观组织及摩擦磨损性能的影响

摘要

研究不同Bi含量对Al-20%Si合金微观组织及摩擦性能的影响.借助金相显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)对Al-20%Si合金进行观察分析.结果表明,随着Bi含量的增加,Al-20%Si合金组织中初晶硅和共晶硅都有不同程度的细化.添加0.75%Bi,块状初晶硅的棱角钝化,尺寸小于50μm;当Bi含量达到1.5%时,初晶硅近似不规则多边形,尺寸进一步减小,棱角更加圆润,共晶硅呈弥散分布,部分呈颗粒状.摩擦磨损试验表明,Bi对Al-20%Si合金摩擦系数以及摩擦力产生影响,摩擦系数从0.73降为0.58,磨损量减少20%.%Experiment was carried out to study the effect of different Bi content on microstructure and friction and wear properties of Al-20% Si alloy. Optical microscopy, scanning electron microscopy and X-ray diffraction were used to analyze the microstructures of the alloys. The results show that with the increase of Bi content, the primary silicon and eutectic silicon of the Al-20%Si alloy have the different degrees of refinement. When the addition of Bi reached 0.75%, the corner angle of the bulk primary Si was passivated, and its size was below 50μm;when the addition of Bi reached 1.5%, the primary Si was similar to irregular polygon , the size was further reduced, and its corner was more smooth,eutectic Si is dispersed, and part are granular. In addition, the research on friction shows that adding Bi has an effect on friction coefficient and friction force of alloy, the friction coefficient decreases from 0.73 to 0.58, and the abrasion loss of alloy have been reduced by 20%.