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研究了未细化和经1.2%的MgCO3细化处理的AZ63镁合金在部分重熔过程中的组织演变,并对其机理进行了分析。结果表明,细化处理和未细化处理的AZ63镁合金经部分重熔后均可获得理想的半固态组织。但细化处理后的球化速度加快,其主要原因是细化处理前后铸态组织中β相的分布不同;未细化的枝晶臂较为发达,晶界面积较大,β相的分布较为分散,在达到共晶温度时几乎消失,固溶到晶粒内部,使相邻的晶粒相连接,并且合并长大。
The microstructure evolution of the non-refined and refined AZ63 magnesium alloy treated with 1.2% MgCO3 was studied during the partial remelting process and its mechanism was analyzed. The results show that the AZ63 magnesium alloy refined and refined can obtain ideal semi-solid structure after partial remelting. However, the speed of nodularity accelerated after refining was mainly due to the different distribution of β phase in the as-cast microstructure before and after refining treatment. The un-refined dendrite arm was more developed, the grain boundary area was larger and the distribution of β phase was more Dispersed, almost disappear when the eutectic temperature is reached, dissolve into the interior of the grains, connect the adjacent grains, and merge and grow.