DD15单晶高温合金的蠕变各向异性  

Anisotropic Creep Behavior of DD15 Single Crystal Superalloy

作　　者：史振学[1] 刘世忠[1] 岳晓岱[1] 李嘉荣[1] Shi Zhenxue;Liu Shizhong;Yue Xiaodai;Li Jiarong(Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]北京航空材料研究院先进高温结构材料重点实验室,北京100095

出　　处：《稀有金属材料与工程》2022年第10期3542-3546,共5页Rare Metal Materials and Engineering

基　　金：National Science and Technology Major Project (J2019-Ⅲ-0008-0052, 2017-VI-0002-0071)。

摘　　要：在定向凝固炉中制备了[001]、[011]和[111]3种不同取向的DD15单晶高温合金,研究了980℃/300 MPa条件下不同取向的蠕变性能。为对比分析不同蠕变时间后的微观组织,蠕变50和100 h后停止试验。采用扫描电镜和透射电镜分析不同取向的合金组织。结果表明,不同取向合金在垂直于生长方向的截面上具有不同的组织特征,[001]取向γ′相为规则的正方形,[011]取向γ′相为矩形,[111]取向γ′相为多边形。合金在980℃/300 MPa条件下的蠕变性能呈现明显的各向异性,蠕变寿命按[111]、[001]、[011]取向的顺序减小,应变量按[001]、[011]、[111]取向的顺序降低。3种取向合金蠕变曲线的共同特征为具有非常短的蠕变第1阶段,与[001]和[111]取向相比,[011]取向合金具有较短的蠕变第3阶段。不同取向合金蠕变后的γ′相具有明显不同的筏排化程度。[001]取向合金的γ′相筏排化速率大于[011]和[111]取向合金。蠕变断裂后,[001]或[111]取向合金的位错密度大于[011]取向合金。DD15 single crystal superalloy with[001],[011]and[111]orientations was cast by seed method in the directional solidified furnace.The creep properties of the alloy with different orientations were investigated at 980°C/300 MPa.In order to obtain the microstructure evolution after different creep time,the creep after 50 and 100 h and the creep fracture of three kinds of tests were investigated.The alloy microstructure with different orientations were investigated by SEM and TEM.The results show that the alloy with different orientations has obviously various microstructure characteristics on the section perpendicular to the crystal growth direction.Theγ′phase with[001]orientation is regular square,that with[011]orientation is rectangular,and that with[111]orientation is polygon.The creep properties of the alloy exhibit obvious anisotropy at 980°C/300 MPa.The creep life of the alloy decreases in the sequence of[111],[001]and[011]orientation.The creep strain of the alloy under different conditions decreases in the sequence of[001],[011]and[111]orientation.The common feature of the creep curves is a very short primary creep stage.Compared with creep curves of the[001]and[111]orientation,the creep curve of[011]orientation has a shorter third creep stage.The degree ofγ′coarsening is obviously different for alloy with different orientations after creep.The rafting speed of[001]oriented sample is larger than that of[011]and[111]oriented sample.After creep fracture,the dislocation network of[001]or[111]oriented alloy is denser and better than that of[011]oriented alloy.

关 键 词：单晶高温合金 DD15 蠕变性能 各向异性 

分 类 号：TG132.3[一般工业技术—材料科学与工程]