锶变质铝硅共晶合金中“临界饱和变质冷却速度”现象的研究

Study on the "Critical Cooling Rates of Saturated Modification" Phenomenon in Al—Si Eutectic Alloys Modified by Strontium

采用新型的连续定向凝固装置考察了不同冷却速度下锶变质Al—Si共晶合金的共晶硅形貌及合金的强度性能。研究发现:当冷却速度大于某一阈值后,继续增加合金的冷却速度,共晶硅尺寸几乎不再变化;强度值也不再增加。且提出了“临界饱和变质冷却速度”的概念。

The new type of continuous directional solidification apparatus is applied to Investigate the morphology of eutectic silicon and the strength of eutectic Al-Si alloys modified by strontium at different rates of cooling. The study indicates when cooling rate is above a given value, further increasing cooling rates will neither change the diameter of the eutectic silicon nor increase the strength of the alloys. The concept of 'crictical cooling rates of saturated modification 'is put forward.