Al-Si合金中Si相的团粒化研究

Spheroidization of Eutectic and Primary Si Crystals in Hypoeutectic and Eutectic Al Si Alloys

利用金相和电子探针等手段研究了AC8C、ZL104和ZL109牌号的亚共晶及共晶Al Si合金中共晶和初晶Si相的团粒化。结果表明,用Sr变质处理附以热处理手段相结合的方法可促使共晶Si相呈团粒状,并均匀分布于铝基体上,加入TiB2粒子可进一步促进共晶Si趋于圆滑,甚至使之团球化。使用杆状Al P中间合金后,可使共晶Al Si合金析出大量初晶Si,获得过共晶组织,并在一定条件下可促使初晶Si晶粒团粒化,提高活塞的金相等级。另外,在Si、Cu和Mg成分一定的条件下可形成一个球状复合相,为获得真正的球状Si相开辟了新思路。

The spheroidization of eutectic and primary Si crystals in AC8C, ZL104 and ZL109A alloys were investigated in this article. Experimental results show that, granular eutectic Si grains, which distribute in Al matrix symmetrically, can be obtained by Sr modification and heat treatment; TiB 2 particles added can further make eutectic Si phases more smooth and even become a spheroid. Eutectic Al Si alloy modified by Al P master alloy rod can produce large number of primary Si crystals, obtaining hypereutectic structure. Furthermore the primary Si can be spheroidized and uniformly distribute in eutectic base, improving the metallographic grade and piston quality. In addition, compound comprised with certain composition such as Si, Cu and Mg can develop a spheroid, this provides a new idea to spheroidize Si phases in Al Si alloys.