复合添加Mn、B对铝硅合金富铁相特征的影响

Effect of B Addition on the Morphology of Iron-Rich Phases in Al-Si Alloy

在含1.0%Fe的铝硅合金中复合加入一定量的Mn和不同量的B,采用OM、SEM、EDS及DSC等手段研究了B含量对铸态组织、富铁相比例及形貌的影响,并探讨了复合添加Mn/B的影响机制。结果表明:适量的B对Al-Si合金晶粒度、富铁相都具有明显的细化作用;添加3%Al-3B时,富铁相体积分数和平均颗粒尺寸分别从6.73%和11.2μm降至4.13%和7.5μm;在3%之内添加Al-3B可抑制粗大初生铁相的形成,促进富铁相由粗大星状初生铁相、大尺寸树枝状、网状共生富铁相向小尺寸致密度高的树枝状、汉字状和粒状富铁相状变;过量的Al-3B易导致多边形初生铁相的出现,但合金组织和共生铁相得到进一步的细化。

The effect of B addition on the morphology of iron-rich phase in Al-Si alloy with ？1.0% Fe and ？1.0% Mn was investigated with optical microscopy, SEM, EDS and DSC. The results show that an appropriate amount of B addition results in an obvious refinement not only on Al-Si alloy grain, but also on the morphology, size and volume fraction of the iron-rich phases. With 3% Al-3B addition, the volume fraction and mean size of the iron-rich phases are reduced to 4.13% and 7.5 μm, respectively. With the increase of Al-3B addition within 3%, the formation of coarse primary iron-rich phase is suppressed, and the primary coarse iron phase, large size dendritic iron-rich phase and netlike iron-rich phase are transformed into small-sized and high-density dendritic, Chinese script shaped and granular iron-rich phase. However, excessive Al-3B addition forms polygon primary iron rich phase, but refines grain size and iron-rich phase.