为了揭示冷却速度对铝硅合金中β相的大小及分布的影响,研究其凝固过程中的自退火效应,设计了一套实验装置并进行实验。对铝硅合金试样的不同壁厚部位中的β相特征进行研究。研究发现,其颗粒的尺寸分布符合对数正态分布。为了研究不同壁厚处以及不同冷却条件下的性能,还进行了布氏硬度实验。实验表明,试样在水中冷却时其硬度比在空气中冷却时更均匀,并且其平均硬度更高。 In order to reveal the effect of cooling rate on the size and distribution of β phase in Al-Si alloy, the self-annealing effect in the solidification process was studied. A set of experimental equipment was designed and tested. The characteristics of β phase in different thickness sections of Al-Si alloy specimens were studied. The study found that the particle size distribution in line with the lognormal distribution. Brinell hardness tests were also conducted to investigate the performance at different wall thicknesses and under different cooling conditions. Experiments show that when the specimen is cooled in water its hardness is more uniform than when it is cooled in air and its average hardness is higher.