抽拉速率对DZ406镍基高温合金组织及元素偏析的影响

Effects of Drawing Rate on Microstructure and Segregation of DZ406 Nickel-based Superalloy

采用快速凝固法(HRS)制备DZ406定向凝固镍基高温合金试样,研究抽拉速率(3、6、9 mm/min)对合金组织及偏析的影响。结果表明,随抽拉速率由3 mm/min增至9 mm/min,合金的一次枝晶间距由580.47μm降至510.29μm,二次枝晶间距由69.15μm降至65.92μm;γ′相形态由不规整的蝴蝶状向排列紧密的立方状转变,尺寸逐渐减小,分别由枝晶间的0.55μm减至0.28μm,枝晶干的0.27μm减至0.17μm;元素偏析程度逐渐减小。碳化物、γ/γ′共晶组织主要分布于枝晶间,碳化物形态由块状向棒状、长条状、颗粒状、网络骨架状进行转变,γ/γ′共晶组织形态由葵花状向块状转变,含量逐渐降低。

DZ406 nickel-based superalloy specimens were prepared by high rapid solidification(HRS),and effects of different drawing rates(3,6,9 mm/min)on microstructure and segregation of the alloy were investigated.The results indicate that with the increase of drawing rate,the primary dendrite space is decreased from 580.47μm to 510.29μm,and the secondary dendrite space is decreased from 69.15μm to 65.92μm.The morphology of γ′phase is transformed from irregular butterfly shape to tightly arranged cubic shape,with the dimension decreased from 0.55μm to 0.28μm in interdendritic and 0.27μm to 0.17μm in dendritic stem,and the segregation degree is decreased.Moreover,carbide and γ/γ′eutectic is mainly distributed among dendrites,where the morphology of carbide is converted from block to rod,long strip,particle and network shell,while that of γ/γ′eutectic phase is transformed from oatmeal to block with decreasing content.