熔模铸造ZL205A铸件偏析形成机理及解决措施

Formation Mechanism of Segregation in Investment Casting ZL205A and its Countermeasures

以航空发动机反推装置用预冷器引气段ZL205A合金熔模铸件为研究对象,采用OM、SEM、EDS等手段,研究了ZL205A合金铸件中点状、带状以及线状等不同形貌偏析缺陷的形成规律及机理。结果表明,点状偏析形成主要原因是由于合金中Ti、Zr等原子团簇聚集;而带状及线状偏析主要是由于凝固过程中形成的Al2Cu共晶偏析导致。通过调整合金的熔炼工艺以及铸造工艺,该铸件偏析程度大幅度减轻。

The formation mechanism of segregation with various morphology of spot,banded and line shape in lead air section of ZL205 Acastings used for the reverser of aero-engine with thin-walled,heteromorphosis and mutant cross section was analyzed by OM（optical microscopy）,SEM（scanning electron microscopy）and EDS（energy dispersed spectrometer）.The results show that the formation of spotshaped segregation in the lead air section of the cooling castings is contributed to the aggregation of Ti and Zr cluster,while the formation of banded and line shape segregation is the result of the Al2 Cu eutectic segreagtion during the solidification process.The segregation degree is relieved greatly through adjusting the remelting and casting process of the alloy.