7175 合金铸锭均匀化工艺研究

Study on homogenization of 7175 alloy ingot

采用光学金相(OM)、扫描电镜(SEM)、差示扫描量热(DSC)等技术对7175合金铸锭均匀化工艺进行研究。结果表明:铸锭中结晶相主要为T相(AlZnMgCu)与Al7Cu2Fe相,大量分布在晶界处,晶内较少;采用450℃/5 h+470℃/24 h对铸锭进行均匀化处理,不但能够消除铸态低熔点非平衡共晶相,而且可以有效促进微量元素Cr以弥散相形式均匀析出。

The homogenization process of 7175 alloy ingot was studied by optical metallography(OM),scanning electron microscopy(SEM)and differential scanning calorimetry(DSC).The results show that the crystallization phases in the ingot are mainly T phases(Al⁃ZnMgCu)and Al7Cu2Fe phases,and a large number of them are distributed in the grain boundary.The homogenization of ingot at 450℃/5h+470℃/24h can not only eliminate the non-equilibrium eutectic phase with low melting point as cast,but also promote the uniform precipitation of trace element Cr in the form of dispersion phase.