【摘要】 采用OM、SEM、EDS等手段，研究了SiC颗粒添加量、颗粒尺寸以及添加温度对Mg-1.0Mn合金晶粒细化效果的影响，并结合基于溶质再分配修正的谢尔（Scheil）凝固模型分析了相应的晶粒细化机理。结果表明，随着SiC颗粒含量、尺寸和添加温度的增加，合金铸态组织的平均晶粒尺寸向均匀细小趋势发展。添加的SiC颗粒不能直接作为α-Mg晶粒的形核质点，而是与Mn反应形成Mn₃Si颗粒作为异质形核的质点，因此SiC的添加量必须与Mn的含量相一致。本试验条件下，最佳的工艺组合为在760℃下添加直径为2μm左右的含量为0.5%的SiC颗粒。更多还原

【Abstract】 The effects of SiC particle addition amount, particle size and addition temperature on the grain refinement effect of as cast microstructure of Mg-1.0Mn alloy were studied by means of OM, SEM and EDS, and the corresponding grain refinement mechanism was analyzed combining Scheil solidification model based on solute redistribution correction. The results showed that the average grain size of as-cast microstructure become uniform and fine with the increase of the SiC content, particle size and addition temperature. The added SiC particles cannot directly act as the nucleation site of α-Mg base phase grain, but reacts with Mn to form Mn3Si particles which can become the core of heterogeneous nucleation. Therefore, the addition amount of SiC must be consistent with the content of the Mn. Under the experimental conditions, the best process combination was 0.5% SiC particles with a diameter of about 2 μm adding at 760 ℃.更多还原