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一、前 言 Al—Si合金是重要的铝合金之一。由于它有良好的铸造性能,耐热、耐磨、耐腐蚀,因而受到广泛重视。但合金中硅常呈粗大的枝状结构,致使韧性和抗拉强度偏低,因而在很长的一段时间内限制了它的广泛应用。只是在人们通过各种途径改变合金中Si的结晶形态(常称之为变质作用),从而提高合金的机械性能之后,Al—Si合金才在铸造中得到广泛的应用与发展。关于“变质作用”的概念,各作者理解并不相同,往往把结构的变质(modification)与机械性
I. Introduction Al-Si alloy is one of the important aluminum alloy. Because of its good casting performance, heat resistance, wear resistance, corrosion resistance, which received widespread attention. However, the alloy often has a coarse, dendritic structure of silicon, resulting in low ductility and tensile strength, which limits its wide range of applications for a long period of time. Only in people through a variety of ways to change the alloy of Si crystal morphology (often referred to as metamorphism), thereby improving the mechanical properties of the alloy, Al-Si alloy was found in the casting has been widely used and development. With regard to the concept of “metamorphism”, the authors understand that they are not the same and tend to modify the structure and the mechanical