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研究在不同的热扩散温度和保温时间下过共晶Al-18%Si合金中共晶硅形貌的演变过程。结果表明,热扩散温度分别为400、450和500℃,保温时间为3h时,随热扩散温度的升高,铸态Al-18%Si合金中粗大针片状共晶硅向短棒状或粒状转变的速度加快;另外,当热扩散温度为400℃,保温时间依次为3h、6h和9h,随着保温时间的延长,粗大针片状的铸态共晶硅逐渐向圆整度较高的粒状转变,且共晶硅颗粒尺寸小于2μm,当保温时间达到12h时,出现了共晶硅颗粒的粗化,部分颗粒的尺寸达到4μm。通过摩擦系数的测定,发现共晶硅颗粒越细小圆整,摩擦系数越小。
The evolution of eutectic silicon morphology in hypereutectic Al-18% Si alloy at different heat diffusion temperature and holding time was investigated. The results show that when the thermal diffusion temperature is 400, 450 and 500 ℃, respectively, and the holding time is 3h, with the increase of thermal diffusion temperature, the coarse needle-shaped eutectic silicon in the as-cast Al-18% In addition, when the thermal diffusion temperature of 400 ℃, holding time followed by 3h, 6h and 9h, with the holding time, the coarse needle-shaped eutectic silicon gradually rounded to the higher Particle transformation, and eutectic silicon particle size of less than 2μm, when the holding time reaches 12h, there eutectic silicon particles coarsening, the size of some particles up to 4μm. Through the determination of the friction coefficient, it is found that the smaller the eutectic silicon particles are, the smaller the friction coefficient is.