Mn/B复合添加对铝硅合金富铁相特征的影响

Effect of compound addition Mn/B on the characteristics of iron-rich phase in Al-Si alloy

摘要:

在含1.0?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，富铁相面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。

Abstract:

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 invesitigated with optical microscopy, SEM, EDS and DSC. The obtained results show that an appropriate amount of B addition results in not only an obvious refinement on Al-Si alloy grain, but also 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 were 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 has been suppressed, and the primary coarse iron phase, large size dendritic iron-rich phase and netlike iron-rich phase are transformed into small size and high density of dendritic, chinese script shaped and granular. However, excessive Al-3B addition leads to the formation of polygon primary iron rich phase and refined grain size and iron-rich phase.