单晶高温合金DD6不同状态下的元素分布与力学行为

发布时间：2018-03-19 12:35

本文选题：镍基单晶高温合金　切入点：元素分布　出处：《材料导报》2017年12期 　论文类型：期刊论文

【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。
[Abstract]:DD6 single crystal superalloys in the direction of [001] were prepared by the helical crystal selection method. The elemental distribution between dendrite and dendritic stem was measured, and the rupture properties and fracture characteristics of the two kinds of alloys were studied by using the pull-out rates of 3mm / min and 8mm / min respectively. The elemental distribution of dendritic and dendritic stem after 0. 1% creep strain was measured by EPMA electron probe. The elastic modulus and hardness of dendrite and dendritic stem were measured by nano indentation instrument. When the drawing rate is small, the dendrite structure of DD6 alloy is thicker, the degree of element segregation is larger, and the tensile rate has little effect on the rupture life of DD6 alloy, and with the increase of creep strain, The difference of elastic modulus and hardness between dendrite and dendrite increases gradually, which is closely related to the redistribution of alloying elements, especially to the redistribution of the refractory elements TaHfFU Mo and NB with the change of creep strain.
【作者单位】：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;
【基金】：航空基金民发专项(2014ZF21028)
【分类号】：TG132.3

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