Cr含量对铸造Al-3Si-0.4Mg合金微观组织的影响

Influence of Cr Contents on Microstructure of the Cast Al-3Si-0.4Mg Alloys

使用Thermo-Calc相图软件计算了不同Cr含量的铸造Al-3Si-0.4Mg合金的相图与凝固过程,并采用重力铸造进行验证。结果表明,试验结果和Thermo-Calc软件中Scheil模块所计算的结果一致,当Cr含量较低时(≤0.13%,质量分数),Cr对合金的微观组织没有明显影响,当Cr含量较高时(≥0.2%),形成了Al13(Cr,Fe)4Si4相。当Cr含量从0.13%增加到0.2%时,合金中富Fe相的平均长度减小,富Fe相的体积分数增加。

Phase diagrams and solidification processes of Al-3 Si-0.4Mg alloys with different Cr contents were calculated by the Thermo-Calc phase diagram software,which were verified by gravity casting.The results reveal that the experimental results are in good agreement with those calculated by Scheil module in Thermo-Calc software.When the contents of Cr is less then 0.13%,the effect of Cr on the microstructure of the alloy can be ignored.When the contents of Cr is more than 0.2%,Al13(Cr,Fe)4Si4 phase can be observed.As the Cr content increased from 0.13% to 0.2%,the average length of the iron-rich phase in the alloy is decreased,and the volume fraction of the iron-rich phase in the alloy is increased.