变形高温合金GH4065A的铸态组织及均匀化研究

Study on as-cast microstructure and homogenization of wrought superalloy GH4065A

应用SEM、DSC等试验方法研究了高温合金GH4065A电渣锭不同部位的铸态组织,并设计不同温度和时长的均匀化工艺制度处理样品,随后研究了不同均匀化制度下样品的微观组织演变和残余偏析指数变化规律。结果表明,铸态GH4065A中主要析出相为γ-γ’共晶相,硼化物相和TiN相,偏析较为严重的元素为Ti、Nb、Mo、W。经1160℃、10 h均匀化处理可以将析出相消除,并使Ti、Nb、Mo的残余偏析指数降至0.2左右,W的残余偏析指数降至0.4左右,是较合理的均匀化条件。生产现场由于铸锭尺寸较大,在1160℃炉内维持20 h左右均匀化时长是一个较为合理的均匀化制度。

The as-cast microstructure of the samples from multiple locations of an ESR ingot of superalloy GH4065 A had been characterised by SEM and DSC,and then evolution of microstructure and residual segregation index of the samples treated under a variety of designed homogenization schemes had been investigated.The results show thatγ-γ’eutectic phase,borides and TiN are the major precipitated phases in the as-cast microstructure of GH4065 A.Ti,Nb,Mo and W are the major segregated elements.After homogenization at 1160℃for 10 h,the precipitated phases mostly dissolves and residual segregation index of Ti,Nb,Mo reduces down to about 0.2,and index of W down to 0.4,which demonstrates homogenization at 1160℃for 10 h is reasonable treatment condition.Due to the large scale of ingots in industrial production,it is acceptable to immerse the ingot in the furnace of 1160℃for 20 h to achieve homogenization.