单晶高温合金DD6不同状态下的元素分布与力学行为  

Elements Distribution and Mechanical Behavior of Single Crystal Superalloy DD6 Under Different Processing Conditions

作　　者：蒋睿哲 顾玉丽[1] 何玉怀[1] 

机构地区：[1]北京航空材料研究院中航工业失效分析中心,航空材料检测与评价北京市重点实验室,材料检测与评价航空科技重点实验室,北京100095

出　　处：《材料导报》2017年第12期93-97,共5页Materials Reports

基　　金：航空基金民发专项(2014ZF21028)

摘　　要：选择3mm/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3mm/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 pre- pared 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 ele- ments 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 ele- ment redistribution especially the redistribution of Ta, Hf, Mo and Nb.

关 键 词：镍基单晶高温合金 元素分布 抽拉速率 蠕变 持久 螺旋选晶法 

分 类 号：TG132.32[一般工业技术—材料科学与工程]