高比功率汽油机在较高温度下使用,工作条件很苛刻,因此,人们用过共晶铝合金代替了亚共晶和共晶铝合金制造活塞。但是过共晶铝合金很难切削加工,需要使用高精度合金钢刀具。普通的亚共晶铝合金(SAE332)或共晶铝合金(F-132)含硅量约9～13％,而过共晶铝合金含硅量很高,在16％以上。亚共晶铝合金较易铸造和机加工。过共晶铝合金活塞有很多优点,其中最主要的优点是消除了活塞的“敲缸”现象。 High specific power gasoline engine used at higher temperatures, the working conditions are harsh, therefore, people have used eutectic aluminum alloy instead of hypoeutectic and eutectic aluminum piston. However, eutectic aluminum alloy is difficult to cut, you need to use high-precision alloy steel cutting tools. Common sub-eutectic aluminum alloy (SAE332) or eutectic aluminum alloy (F-132) silicon content of about 9 to 13%, while hypereutectic aluminum content of silicon is very high, more than 16%. Sub-eutectic aluminum alloy easier casting and machining. Hypereutectic aluminum piston has many advantages, of which the most important advantage is to eliminate the piston “knock cylinder” phenomenon.