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一、前 言 Al—Si合金的性能在很大程度上与共晶硅的尺寸形态有关。共晶硅呈粗大片状时,合金的力学性能尤其是延伸率很低。细小圆整的共晶硅均匀地分布于基体上,则可望获得良好的综合性能。 以往,人们只是考虑通过铸造手段来控制共晶硅的尺寸形态。激冷(如金属型铸造)能促进共晶硅分枝细密,但并不改变共晶硅的生长方式且受生产条件的限制。对合金进行变质处理,也能改变共晶硅的尺寸形态,人们在这方面做了不少工作。但是,迄今所有试验的变质剂均不能使共晶
I. INTRODUCTION The properties of Al-Si alloys are largely related to the size and shape of eutectic silicon. Eutectic silicon is a large sheet, the alloy mechanical properties, especially the elongation is very low. Fine round eutectic silicon evenly distributed on the substrate, it is expected to get a good overall performance. In the past, people only considered by casting means to control the size and shape of eutectic silicon. Chilled (such as metal casting) can promote eutectic silicon branching fine, but does not change the way eutectic silicon growth and production conditions. Metamorphism of the alloy can also change the size and shape of eutectic silicon, people have done a lot of work in this regard. However, none of the metamorphic agents tested so far eutectic