GH4068合金管材成形工艺及力学性能研究  

Study on Forming Process and Mechanical Properties of GH4068 Alloy Pipe

作　　者：崔传勇[1] 白英伯 张瑞 周子荐 周亦胄[1] 孙晓峰[1] CUI Chuanyong;BAI Yingbo;ZHANG Rui;ZHOU Zijian;ZHOU Yizhou;SUN Xiaofeng(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,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,沈阳110016

出　　处：《航空制造技术》2022年第10期36-43,共8页Aeronautical Manufacturing Technology

基　　金：国家重点研发计划项目(2017YFA0700703、2019YFA07053000);国家科技重大专项项目(2019–VI–0006–0120);辽宁省博士启动基金项目(2020–BS–007);中国科学院金属研究所创新基金项目(2021–PY09)。

摘　　要：采用铸态直接包套热挤压和开坯+挤压两种工艺制备了GH4068合金管材,通过热压缩模拟试验及力学性能测试研究了两种制备工艺条件下合金管材的成形及使用性能。结果表明,GH4068合金在γ′相完全固溶温度以下加工时具有良好的热变形能力,铸态合金经高温退火后晶粒组织粗大,变形协调性较差,直接挤压时最佳变形温度较高(1130℃);铸锭经开坯后得到的细晶组织有助于提高变形能力,降低热挤压加工温度,开坯合金在1090℃、0.1~1s^(–1)应变速率下变形后动态再结晶体积分数达到95%以上。开坯+挤压得到的管材晶粒尺寸约为6.8μm,细晶组织与晶界处初生γ′相有助于合金拉伸性能的提高,其750℃屈服强度达到1088MPa。开坯挤压管材细晶组织中的大量晶界的存在影响了合金的高温持久性能,其持久寿命低于晶粒粗大(约35μm)的铸态挤压管材。GH4068 alloy pipes were prepared by casting directly canned hot extrusion and blooming+extrusion.The forming and service properties of the alloy pipes under two kinds of preparation conditions were studied by thermal compression simulation test and mechanical property test.The results show that GH4068 alloy has great thermal deformation ability when processed belowγ′complete solution temperature.After high-temperature annealing,the grain structure of as-cast alloy is coarse and the deformation coordination is poor.The optimum deformation temperature is higher(1130℃)during direct extrusion;The fine grain structure obtained after blooming is helpful to improve the deformation ability and reduce the hot extrusion temperature.The dynamic recrystallization volume fraction of the bloom alloy after deformation at 1090℃and 0.1–1s^(–1) strain rate is more than 95%.The grain size of the tube obtained by blooming+extrusion is about 6.8μm.Fine grain structure and primary γ′phase at grain boundary contribute to the improvement of the tensile properties of the alloy,and its yield strength at 750℃reaches 1088MPa.The existence of a large number of grain boundaries in the fine grain structure of the bloomed+extruded pipe affects the high temperature stress-rupture property of the alloy,and its endurance life is lower than that of the as-cast extruded pipe with coarse grain(about 35μm).

关 键 词：变形高温合金 管材成形 热挤压工艺 热变形行为 力学性能 

分 类 号：V261[航空宇航科学与技术—航空宇航制造工程] TG376.2[金属学及工艺—金属压力加工]