选择3 mm/min和8mm/min两种抽拉速率通过螺旋选晶法制备[001]方向的DD6单晶高温合金,测试合金枝晶间与枝晶干的元素分布,研究了两种工艺合金的持久性能和断裂特征;利用EPMA电子探针测试了3 mm/min抽拉速率DD6合金经0.1％、0.2％、0.5％蠕变应变后枝晶间与枝晶干的元素分布,并通过纳米压痕仪测试了枝晶间与枝晶干的弹性模量和硬度.结果表明,抽拉速率较小时DD6合金枝晶组织更粗大,元素偏析程度较大,抽拉速率对合金持久寿命的影响不大;随着蠕变应变的增加,合金枝晶间与枝晶干弹性模量和硬度的差值逐渐增大,这与合金元素的再分布紧密相关,特别是与难熔元素Ta、Hf、Mo和Nb随着蠕变应变的变化而发生再分布有关.%The element distribution between dendrite cores and interdendritic region of DD6 alloys at [001] orientation prepared by spiral grain selection method with different withdrawing rate (8 mm/min,3 mm/min) was analyzed by EPMA.The fracture characteristic and rupture life of single crystal superalloy DD6 were also investigated.The effect of creep rate (0.1％,0.2％ and 0.5 ％) on segregation of main elements,elastic modulus and hardness of single crystal superalloy DD6 were investigated by EMPA and Hysitron Ti-950.The results showed that the alloy had coarse dendrite structure and high segregation coefficient of main elements under low withdrawing rate,and different withdrawing rate has little effect on rupture life.With the increase of creep rate,the difference of hardness and elastic modulus between dendrite cores and interdendritic increased,which was mainly caused by the element redistribution especially the redistribution of Ta,Hf,Mo and Nb.
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