型壳保温方式对一种等轴晶镍基铸造高温合金组织和力学性能的影响  

Effects of Shell Insulation Methods on Microstructure and Mechanical Properties of an Equiaxed Nickel-Based Cast Superalloy

作　　者：张茂源 欧美琼 冉兴 侯坤磊 曹建 马颖澈[1,3] Zhang Maoyuan;Ou Meiqiong;Ran Xing;Hou Kunlei;Cao Jian;Ma Yingche(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Taiyuan University of Science and Technology,Taiyuan 030024,China;Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Guizhou Anji Aviation Precision Casting Co.,Ltd,Anshun 561000,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,辽宁沈阳110016 [2]太原科技大学,山西太原030024 [3]中国科学院金属研究所核用材料与安全评价重点实验室,辽宁沈阳110016 [4]贵州安吉航空精密铸造有限责任公司,贵州安顺561000

出　　处：《稀有金属材料与工程》2024年第3期757-767,共11页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(52001314);国家科技重大专项(J2019-Ⅶ-0002-0142,J2019-Ⅵ-0004-0118)。

摘　　要：通过设计型壳保温方式改变合金冷却速率,分析了冷却速率对一种等轴晶镍基铸造高温合金K4750显微组织和室温拉伸性能的影响。设计的4种型壳保温方式包括填砂、试棒不包保温毡、包单层保温毡和包双层保温毡,型壳试棒处的冷却速率大小顺序为:试棒不包保温毡≥填砂>包单层保温毡≥包双层保温毡。标准热处理后,型壳填砂的试棒室温抗拉强度最高(1115 MPa),试棒不包保温毡次之(1095 MPa),包单层保温毡与包双层保温毡最差(分别为950和952.5 MPa)。室温屈服强度、延伸率和断面收缩率变化规律与室温抗拉强度相同。采用OM、SEM以及EBSD等方法表征合金显微组织,发现型壳填砂、试棒不包保温毡、包单层保温毡和包双层保温毡的试棒晶粒均为等轴晶,平均晶粒尺寸分别为176、167、325、315μm。填砂和试棒不包保温毡合金冷速较快,形成的细小等轴晶在应力条件下易于协调变形,凝固过程形成的MC型一次碳化物更细小且主要呈块状,有利于抑制变形时微孔洞、裂纹的扩展,显著提高了合金室温拉伸性能。相反,型壳包单层和双层保温毡的合金冷速较慢,形成的大尺寸等轴晶不利于晶粒间的协调变形,析出的大尺寸长条状MC型一次碳化物促进孔洞、微裂纹的萌生与扩展,使合金室温强度和塑性均显著下降。The effects of cooling rate on microstructure and room temperature tensile properties of equiaxed nickel-based cast superalloy K4750 were studied by designing shell insulation methods.Four types of insulation methods were designed,including sand-filled method,test bars without insulation felt,wrapped single-layer insulation felt and wrapped double-layer insulation felt,and the order of cooling rate at the test bars of the shell is test bars without insulation felt≥sand-filled method>wrapped single-layer insulation felt≥wrapped double-layer insulation felt.After standard heat treatment,the test bar with sand-filled shell has the highest room temperature tensile strength(1115 MPa),the test bar without insulation felt has the second highest strength(1095 MPa),and the single-layer insulation felt and the double-layer insulation felt have the worst strengths of 950 and 952.5 MPa,respectively.The microstructures of the alloy were characterized by OM,SEM and EBSD.The results show that the grains of sand-filled method,test bars without insulation felt,single-layer insulation felt and double-layer insulation felt are equiaxed crystals,and the average grain sizes are 176,167,325 and 315μm,respectively.The cooling rate of the sand-filled and test bars without insulation felt alloys is faster,the formation of small equiaxed crystals can more easily coordinate deformation in the stress conditions,and the precipitated MC-type primary carbide is finer and mainly in the form of blocks,which is conducive to inhibit the expansion of microvoids and cracks during deformation,significantly improving the tensile properties of the alloy at room temperature.On the contrary,the cooling rate of the alloys prepared by single-layer insulation felt and double-layer insulation felt is slower,the formed large-size equiaxed crystals are not conducive to the coordinated deformation between the grains,and the precipitation of MC-type primary carbide with large size and long strip shape promotes the emergence and expansion of holes and microc

关 键 词：等轴晶 镍基高温合金 型壳保温方式 晶粒尺寸 MC型一次碳化物 室温拉伸性能 

分 类 号：TG146.15[一般工业技术—材料科学与工程]