晶界取向差对双晶高温合金常温和高温拉伸性能的影响  

Effect of Grain Boundary Misorientation on Tensile Properties of Bi-crystal Superalloy at Ambient and High Temperatures

作　　者：马修戈 吴庆辉 庞建超[1] 刘增乾[1,2] 李守新 骆凯伦[3] 张哲峰 MA Xiuge;WU Qinghui;PANG Jianchao;LIU Zengqian;LI Shouxin;LUO Kailun;ZHANG Zhefeng(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;AECC Beijing Institute of Aeronautical Materials,Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing 100095,China)

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016 [3]中国航发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：《材料研究学报》2025年第2期81-91,共11页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51871224,52130002,52321001);两机基础科学中心项目(P2022-C-Ⅳ-001-001)。

摘　　要：采用双籽晶法制备一系列具有特定晶界取向差(GBs)的第二代双晶高温合金并分别在常温和760℃进行拉伸实验,用扫描电子显微镜(SEM)表征晶界组织并研究了晶界取向差对这种双晶高温合金拉伸性能的影响。结果表明:这种双晶合金的拉伸性能随着晶界取向差的增大而降低,但是在不同温度拉伸性能降低的趋势不同。常温抗拉强度随着晶界取向差的增大逐渐降低;760℃抗拉强度在晶界取向差小于8°时几乎不变,晶界取向差为8°~12°时极快地降低。常温拉伸断裂后的伸长率不随晶界取向差的变化而变化,760℃断后伸长率在晶界取向差为0°~4°和8°~12°时极快地降低。随着晶界取向差的增大,760℃拉伸断裂方式由类解理断裂转变为沿晶断裂,常温拉伸的断裂方式为解理断裂。最后用断裂机制能量模型定性解释了在760℃拉伸断裂机制的转变:随着晶界取向差的增大晶界结构逐渐复杂,晶界开裂能量门槛的降低和晶界能量积累速度的提高使拉伸断裂机制由类解理断裂转变为沿晶断裂。A series of the second generation bi-crystal superalloys with specific misorientation grain boundaries(GBs)were prepared by the twin crystal seed method,and then their microstructure of GBs was characterized by means of scanning electron microscopy(SEM),meanwhile their tensile properties were examined comparatively at ambient temperature and 760℃.Therewith,the effect of GBs misorientation on the tensile properties of single crystal superalloy can be elucidated clearly.Results show that,the tensile properties decrease with the increase of misorientation,but there is a difference in the decreasing trend for tensile properties at different temperature.At ambient temperature,the tensile strength continuously decreases and the elongation is unchanged with the increase of GBs misorientation.However,at 760℃,the tensile strength is almost unchanged within misorientation below 8°,and decreases rapidly between 8°and 12°,but the elongation decreases rapidly in misorientation ranges of 0°~4°and 8°~12°.With the increase of GBs misorientation,the tensile fracture mechanism changes from cleavage-like fracture to intergranular fracture at 760℃,but the tensile fracture mechanism is always cleavage fracture at ambient temperature.Finally,an energy model was proposed to qualitatively explain the competitive relationship between the two fracture mechanisms during the tensile fracture process at 760℃.

关 键 词：金属材料 高温合金 取向差 拉伸行为 实验温度 

分 类 号：TG132.32[一般工业技术—材料科学与工程]