共晶硅立体形态对铝硅合金力学行为的影响

EFFECTS OF THE STEREO-MORPHOLOGY OF EUTECTIC SILICON ON THE MECHANICAL BEHAVIOURS OF Al-Si ALLOYS

本文采用全腐蚀的方法,考察了热处理时共晶硅立体形态的变化过程以及Na变质的影响,表明Na变质使共晶硅在热处理时迅速粒状化为近等轴颗粒。从理论上分析了共晶硅立体形态对铝硅合金力学行为的影响,并通过对合金的力学性能测试和断口电镜分析进行验证,指出了可以通过Na变质和热处理综合控制共晶硅形态以提高合金的韧性。

In this paper,eutectic silicon particles are etched out from specimens of Al-11.3Si alloys and observed by SEM to study the change in stereo-morphology of eutectic silicon and the effect of modification with sodium on it.Results show that when modified with sodium,eutectic silicon granulates quickly and changes into nearly equiaxial particles during heat treatment.Effects of the stereo-morphology of eutectic silicon on the mechanical behaviours of the alloy are analysed theoretically and related to the results of test on mechanical properties and SEM observation on fracture faces of the alloy.It is suggested that the morphology of eutectic silicon can be controlled by both Na modification and heat treatment in order to improve the ductility of the alloy.