Al-6.1Zn-2.6Mg-1.6Cu超高强铝合金铸锭均匀化处理研究

Homogenization treatment of ingot of Al-6.1Zn-2.6Mg-1.6Cu higher strength aluminum alloy

采用金相组织和DSC分析方法研究了Al-6.1Zn-2.6Mg-1.6Cu超高强铝合金半连续水冷铸锭均匀化处理过程的过烧温度及组织转变。结果表明,Al-6.1Zn-2.6Mg-1.6Cu超高强铝合金的铸态组织中存在大量的非平衡凝固初生共晶体,其熔化温度为478℃;在470℃均匀化过程中该合金铸锭中的初生共晶体在向基体溶解的同时还转变成熔点约为490℃的产物;在470℃均匀化处理时间达到72h时,合金中的初生共晶体全部消失,但由初生共晶体转变而形成的熔点约为490℃的产物在470℃均匀化处理过程不能被完全消除。

The overheat temperature and mierostrueture transformation during homogenization of semi-continuously east ingot of Al-6.1Zn-2.6Mg-1.6Cu higher strength aluminum alloy were studied with metallographie and DSC analysis. The results show that a lot of primary eutectic exists in the microstructure of the alloy as-cast, whose melting temperature is 478℃; Two processes were found during 470℃ homogenization, one is that the primary eutectic dissolves into the matrix, the other is that the primary eutectic transforms into another phase whose melting temperature balancing with matrix of the alloy is about 490℃ ; When the time of homogenization treatment at 470℃ lasts 72 h, the primary eutectic in alloy disappears, but even lasting 96 h, the new phase from primary eutectic can＇t dissolve entirely.