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研究了等温热处理对AZ61稀土镁合金半固态组织的影响,结果表明:随着等温热处理温度的升高,铸态合金中的初始枝晶组织演变成了半固态非枝晶组织,经过了粗化、组织分离和球化三个过程。在等温热处理过程中,稀土La的加入阻碍了原子向固相粒子的聚集和固相粒子的合并,抑制了固相粒子的进一步长大,使半固态非枝晶组织更加细小。经过不同保温时间后,不规则的大块状组织开始球化,形成大量的近球形颗粒。但是,随着保温时间的进一步延长,球化的颗粒开始粗化长大且在颗粒内形成了大量的液岛。枝晶组织的球化过程,包括二次枝晶壁消失和Ostwald熟化。
The effect of isothermal heat treatment on the semi-solid microstructure of AZ61 rare earth magnesium alloy was studied. The results show that the initial dendritic structure in as-cast alloy evolves into semi-solid dendritic structure with the increase of isothermal heat treatment temperature, After the coarsening, organizational separation and the ball of the three processes. In the isothermal heat treatment process, the addition of rare earth La hinders the aggregation of the atoms to the solid particles and the solid particles, inhibits the further growth of the solid particles and makes the semi-solid non-dendritic structure finer. After different holding time, the irregular massive bulk began to spheroidize, forming a large number of near-spherical particles. However, with the further extension of the holding time, the pelletized particles began to coarsen and formed large amounts of liquid islands in the pellets. Dendritic microstructure of the ball, including the disappearance of secondary dendrite wall and Ostwald ripening.