高博 王磊 梁涛沙 刘杨 宋秀 曲敬龙. 定向凝固U720Li合金的高温塑性变形行为[J]. 金属学报, DOI: 10.11900/0412.1961.2015.0374.

摘要 相关文章 Metrics 全文: PDF(1406 KB)   摘要: 采用热模拟实验研究了定向凝固与等轴晶U720Li合金的高温塑性变形行为,利用OM,SEM和EBSD分析了不同变形条件下合金的组织特征及动态再结晶机制.结果表明,定向凝固与等轴晶合金的变形抗力均随变形温度升高而降低.定向凝固U720Li合金沿垂直柱状晶方向变形时变形抗力较低,枝晶间协调变形能力良好,未出现裂纹.与等轴晶合金相比,相同变形条件下定向凝固合金的动态再结晶组织均匀;高温塑性变形过程中,定向凝固合金的动态再结晶主要以晶界弓弯和位错塞积方式形核.定向凝固U720Li合金的变形激活能为766 kJ/mol,比等轴晶合金降低了38.6 %,定向凝固合金呈现出更好的热加工特性. 关键词 ： 定向凝固,  U720Li合金,  热加工塑性,  动态再结晶     Abstract：U720Li, a kind of precipitation type nickel-based superalloy, shows excellent mechanical properties at elevated temperature, which is also known as the difficult-to-deform alloy because of the high-alloying. To solve its deformation problem, new methods would be developed to enlarge the temperature deforming window and improve its plasticity. The hot compression deformation behaviors of directionally solidified and equiaxed grain U720Li alloys were studied by the MMS-300 testing system, as well as the dynamic recrystallization nucleation and growth mechanisms during the hot deformation were discussed. The microstructural characteristics of the alloy under different deformation conditions were examined using OM, SEM and EBSD. The results show that the deforming resistances of both directionally solidified and equiaxed grain U720Li alloys decrease with the increasing of deforming temperature. When the angle ? between the compression deforming direction and dendrite growth direction is 90°, the deforming resistance of directionally solidified U720Li alloy would be lower. With this direction, the coordination deformation between the dendrites becomes better and no crack can be found after deformation, which indicates that the deforming ability is best along ????90° and it can be considered as the optimal deforming direction for directionally solidified U720Li alloy. Compared with equiaxed grain alloy, directionally solidified U720Li alloy performs higher deformation ability and more homogenous microstructures. During the deformation of directionally solidified U720Li alloy, bulging nucleation of grain boundary migration and dislocation pile-up induced nucleation are found as the main mechanism for the nucleation of dynamic recrystallization. In addition, the deformation activation energy of directionally solidified U720Li alloy is 766 kJ/mol, which is 482 kJ/mol lower than that of equiaxed grain alloy, indicating the directional solidified U720Li alloy exhibits better hot-working plasticity. Key words： directional solidification    U720Li    hot-working plasticity    dynamic recrystallization 收稿日期: 2015-07-10      ZTFLH:  TG 319，TG113.25+3   基金资助:国家自然科学基金项目;国家自然科学基金项目;国家高技术研究发展计划项目 服务 把本文推荐给朋友 加入引用管理器 E-mail Alert RSS 作者相关文章 高博 王磊 梁涛沙 刘杨 宋秀 曲敬龙 44.8K 链接本文: https://www.ams.org.cn/CN/Y0/V/I/0 [1] 郑德宇, 夏玉峰, 曾扬, 周杰. 水平集法模拟GH4706合金动态再结晶过程[J]. 金属学报, 2025, 61(9): 1425-1437. [2] 张洺川, 徐勤思, 刘意, 蔡雨升, 牟义强, 任德春, 吉海宾, 雷家峰. 热压温度对TC4合金扩散连接区组织与性能的影响[J]. 金属学报, 2025, 61(8): 1183-1192. [3] 杨明辉, 李星吾, 孙崇昊, 阮莹. 定向凝固与固态相变双联协控下Monel K-500合金的组织和力学性能[J]. 金属学报, 2025, 61(4): 561-571. [4] 包成利, 李豪, 胡励, 周涛, 唐明, 何曲波, 刘相果. 固溶态Mg-10Gd-6Y-1.5Zn-0.5Zr合金热加工图构建及微观组织演变[J]. 金属学报, 2025, 61(4): 632-642. [5] 周雯慧, 熊锦涛, 黄思程, 王鹏昊, 刘勇. AZ31镁合金双峰组织形成机制及其变形行为[J]. 金属学报, 2025, 61(3): 488-498. [6] 吴宇轩, 唐子渊, 张保泽, 郭晓玉, 罗颖, 刘铁, 王强. 强磁场下Al-Si共晶合金定向凝固组织演变及溶质迁移行为[J]. 金属学报, 2025, 61(11): 1615-1624. [7] 刘光辉, 王卫国, Rohrer Gregory S, 陈松, 林燕, 童芳, 冯小铮, 周邦新. 高温压缩变形Al-Zn-Mg-Cu合金动态再结晶后的{111}/{111}近奇异晶界[J]. 金属学报, 2024, 60(9): 1165-1178. [8] 朱绍祥, 王清江, 刘建荣, 陈志勇. TC19合金铸锭中Zr、Mo元素的宏观偏析行为[J]. 金属学报, 2024, 60(7): 869-880. [9] 杨瑞泽, 翟汝宗, 任少飞, 孙明月, 徐斌, 乔岩欣, 杨兰兰. 1Cr22Mn16N高氮奥氏体不锈钢塑性变形连接中界面组织演化及愈合机制[J]. 金属学报, 2024, 60(7): 915-925. [10] 陈胜虎, 王琪玉, 姜海昌, 戎利建. δ-铁素体对钠冷快堆用316KD奥氏体不锈钢热变形行为和动态再结晶的影响[J]. 金属学报, 2024, 60(3): 367-376. [11] 张健, 王莉, 谢光, 王栋, 申健, 卢玉章, 黄亚奇, 李亚微. 镍基单晶高温合金的研发进展[J]. 金属学报, 2023, 59(9): 1109-1124. [12] 马德新, 赵运兴, 徐维台, 王富. 重力对高温合金定向凝固组织的影响[J]. 金属学报, 2023, 59(9): 1279-1290. [13] 李景仁, 谢东升, 张栋栋, 谢红波, 潘虎成, 任玉平, 秦高梧. 新型低合金化高强Mg-0.2Ce-0.2Ca合金挤压过程中的组织演变机理[J]. 金属学报, 2023, 59(8): 1087-1096. [14] 李福林, 付锐, 白云瑞, 孟令超, 谭海兵, 钟燕, 田伟, 杜金辉, 田志凌. 初始晶粒尺寸和强化相对GH4096高温合金热变形行为和再结晶的影响[J]. 金属学报, 2023, 59(7): 855-870. [15] 苏震奇, 张丛江, 袁笑坦, 胡兴金, 芦可可, 任维丽, 丁彪, 郑天祥, 沈喆, 钟云波, 王晖, 王秋良. 纵向静磁场下单晶高温合金定向凝固籽晶回熔界面杂晶的形成与演化[J]. 金属学报, 2023, 59(12): 1568-1580. Viewed Full text Abstract Cited   Shared      Discussed