DD99单晶高温合金的高温组织演化研究  

Microstructure Evolution of Single Crystal Super-Alloy DD99 at High Temperature

作　　者：李卫军 许军锋[2] 侯春梅 董镈珑 LI Weijun;XU Junfeng;HOU Chunmei;DONG Bolong(AECC Xi＇ an Aero Engine Ltd.,Xi＇ an 710021,China;School of Materials Science and Chemical Engineering,Xi＇an Technological University,Xi＇ an 710021,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]中国航发西安航空发动机有限公司,西安710021 [2]西安工业大学材料与化工学院,西安710021 [3]哈尔滨工业大学材料与工程学院,哈尔滨150001

出　　处：《西安工业大学学报》2018年第4期364-370,376,共8页Journal of Xi’an Technological University

摘　　要：为了研究DD99镍基单晶高温合金的高温组织变化规律,通过高温热处理炉对DD99单晶高温合金进行了不同加热温度和保温时间的试验.采用场发射扫描电镜和显微硬度计分别对不同热处理状态的试样进行组织观察和显微硬度的测试.结果表明:随着温度的升高,保温时间的延长,DD99中的γ′相会发生回熔、连接及合并,尺寸不断增加,然后在γ基体通道中形成二次的颗粒状γ′相,该二次相会随温度的升高逐渐长大.二次γ′相的长大程度和Al、Nb等元素的扩散密切相关.性能试验也表明DD99单晶高温合金在保温100h后的试样随加热温度升高存在着明显的变化趋势,即硬度先降低后升高.A study of the microstructure evolution of a single crystal super-alloy DD99 at different temperatures for different lengths of time is made by an SEM and micro-hardness meter. The result shows that with the temperature and the length of time increasing,the γ＇ phase in the DD99 will melt back, connect, merge and its size will increase. Then the gallery in the γ phase matrix produces the granular secondary γ＇ phase, which grows up with an increase in temperature. It is found that the degree of the growth of the secondary γ＇ phase depends on the diffusion of A1, Nb in the γ phase matrix. The hardness test also indicates that the DD99 whose temperature has been kept constant for 100 h will change obviously with the heating temperature increasing, its hardness decreasing first and then increasing.

关 键 词：单晶高温合金 二次γ′相 高温组织 显微硬度 

分 类 号：TG132[一般工业技术—材料科学与工程]