半固态浆料的冷却速率对组织的影响

摘要

To investigate the effect of cooling rate of semi-solid slurry on microstructure, the water-cooling slope method was used to prepare semi-solid A356 aluminum alloy slurry. The results show that when the cooling rate is more than 26.4 ℃/s, the primary α( Al) in semi-solid slurry is mainly composed of fine dendritic and rose-shape crystal; the cooling rate is 14.0-20.6 ℃/s, the primary α(Al) is mainly composed of spherical, near-spherical grains and some small rose-shape crystal; the cooling rate is 5.0-14.0 ℃/s, the primary α( Al) is mainly composed of spherical and near-spherical grains. The cooling rate of 5.0-15.0 ℃/s is better. The faster the cooling rate is, the finer average grain diameter will be, and the lower shape factor will be.%为了研究半固态浆料的冷却速率对微观组织的影响,采用水冷冷却斜槽来制备半固态A356铝合金浆料.结果表明:当冷却速率大于26.4℃/s时,半固态浆料中的初生α(Al)全部由细小的枝晶和蔷薇晶组成；当冷却速率为14.0～20.6℃/s时,初生α(Al)主要由球形、近球形晶粒和一些细小的蔷薇晶组成；当冷却速率为5.0～14.0℃/s时,初生α(Al)主要由球形和近球形晶粒组成.适宜的冷却速率为5.0～15.0℃/s.冷却速率越快,晶粒平均直径越细小,但形状因子越低.