Al-Si合金铸铁的组织变化规律及其理论解释

The microstructural change in Al-Si alloyed cast irons and its theoretical explanation

研究了 Al-Si合金铸铁的组织结构随 Al含量变化而变化的规律 .结果表明 ,在中 Al中 Si范围内 ,Al-Si合金铸铁的石墨数量、α相、M3C和 ε( Al Fe3C)相均随 Al含量变化而有规律地变化 .当 Al质量分数小于4%时 ,石墨数量随 Al含量增加而增加 ,M3C随之减少 ,α相增加 ;当 Al含量大于 4%时 ,石墨数量随 Al质量分数增加而减少 ,ε相随之增加 ,α相减少 .上述组织结构变化规律可用“固体与分子经验电子理论”解释 ,通过合金元素的价电子结构确定其在合金中所起的作用 。

The microstructural changes that take place with Al content's change in Al Si alloyed cast irons (2.35%~8.88%Al,1.61%~4.68%Si) is studied in the paper .The results indicate that graphite, α phase,M 3C and ε(AlFe 3C) phase amount of Al Si alloyed cast irons vary with Al content change within the range of medium Al and Si. When Al content is less than 4%,the amount of graphite and α phase will increase and M 3C decrease with an increase of Al content. When Al content is more than 4%, the amount of graphite and α phase decrease and ε phase will increase. Those changes can be explained by “the empirical electron theory of solids and molecules”. The role of elements can be identified by the valence electron structural parameters of a phase. It is of great importance to composition design of alloyed cast irons of this kind.