凝固条件对铝硅合金凝固组织影响的研究

Influence of heat transfer condition onsolidification structure of Al-Si alloys

通过一种近定向凝固的实验装置研究了不同保温温度、冷却条件对铝合金等轴晶形核率、柱状晶形核率、柱状晶向等轴晶转变位置的影响规律,试验结果表明:降低保温温度水温,会增大等轴晶区的面积,并且会增大柱状晶和等轴晶的形核率;水冷和油冷比吹风冷却增大铸件柱状晶和等轴晶的形核率,但是会减少等轴晶区的面积,其中水冷更为明显一些.最后根据正交试验获得的CET位置实验结果,针对本文的实验条件,提出了具有一定预测精度的CET转变判据.

Effects of different holding temperatures and cooling conditions on nucleation rates of equiaxed grain,columnar grain,and their transition position in aluminum alloys were investigated by quasi directional solidification equipment.The experimental results show that decreasing holding temperature increases area of the equiaxed grain and the nucleation rates of the equiaxed and columnar grains.Compared with blast air cooling,water and oil cooling,particularly the water cooling,increases the nucleation rates and reduces the area of equiaxed grain.A CET transition criterion with certain prediction accuracy was proposed for the applied test conditions based on orthogonal experimental results of CET position.