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Sr作为变质剂加入到Al Si合金中能导致共晶硅的形态从粗大的片状 (或称为针状 )转变为细小的纤维状 ,但同时也促进了柱状枝晶的形成。当Al 5%Ti 1%B加入量低于 0 8%时 ,α枝晶有等轴化趋向 ,柱状枝晶的主干长度缩短 ,对共晶硅的形态与尺寸没有显著的影响 ,尽管共晶团尺寸略有下降。但当Al 5%Ti 1%B加入量超过 0 8%后 ,其对Sr变质作用的有害影响显现出来 ,α Al枝晶数量减少 ,出现初晶硅 ,共晶硅尺寸变大。随着加入量进一步增加 ,最终转变为未变质组织。所有的结果表明 :熔体中有效Sr量随着Al 5%Ti 1%B中间合金加入量的增加而降低 ,这与Sr和Ti之间的交互作用有关
The addition of Sr as a modifier to the Al Si alloy can cause the morphology of the eutectic silicon to change from a coarse sheet (or acicular) to a fine fibrous one, but at the same time it promotes the formation of columnar dendrites. When the content of Al 5% Ti 1% B is less than 0 8%, the α dendrites tend to have equiaxed orientation, and the length of the trunk dendrites decreases, which has no significant effect on the morphology and size of eutectic silicon. Mission size slightly decreased. However, when the amount of Al 5% Ti 1% B exceeds 0 8%, the detrimental effect on Sr metamorphism appears. The amount of α Al dendrite decreases and the size of primary and secondary eutectic silicon becomes larger. With the addition of further increase, eventually transformed into non-metamorphic tissue. All the results show that the effective Sr content in the melt decreases with the addition of Al 5% Ti 1% B master alloy, which is related to the interaction between Sr and Ti