• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2022, Vol. 58 ›› Issue (16): 110-120.doi: 10.3901/JME.2022.16.110

• 特邀专栏: 高性能塑性成形制造(上) • 上一篇    下一篇

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基于LAM技术研究GH4742合金热力耦合作用下显微组织演变

张文文1, 刘鑫刚1, 李海柱1, 贺旖旎1, 柯雨蛟1, 秦鹤勇2, 田强2   

  1. 1. 燕山大学机械工程学院 秦皇岛 066004;
    2. 钢铁研究总院高温材料研究所 北京 100081
  • 收稿日期:2021-11-30 修回日期:2022-03-30 出版日期:2022-08-20 发布日期:2022-11-03
  • 通讯作者: 刘鑫刚(通信作者),男,1978年出生,博士,教授,博士研究生导师。主要研究方向为大型锻件工艺及优化、航空材料与工艺、动态原位分析技术与全域高通量表征。E-mail:lxg@ysu.edu.cn
  • 作者简介:张文文,男,1981年出生,高级实验师。主要研究方向为高温合金显微组织调控及性能。E-mail:zww@ysu.edu.cn
  • 基金资助:
    国家重大科技专项资助项目(2017-VI-0018-0090)

Study on Microstructure Evolution of GH4742 Alloy under Thermo-mechanical Coupling Based on LAM Technology

ZHANG Wenwen1, LIU Xingang1, LI Haizhu1, HE Yini1, KE Yujiao1, QIN Heyong2, TIAN Qiang2   

  1. 1. College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004;
    2. High Temperature Materials Research Division, Central Iron and Steel Research Institute, Beijing 100081
  • Received:2021-11-30 Revised:2022-03-30 Online:2022-08-20 Published:2022-11-03

摘要: 晶粒尺寸控制对于金属材料获得优异的力学性能至关重要,尤其是析出相含量较高的镍基高温合金,热变形和固溶处理时,再结晶、晶粒长大过程中析出相与晶粒的相互作用复杂。此外,传统小试样热压缩模拟方法无法满足研究需求。以GH4742合金为研究对象,通过较大尺寸双锥试样在变形温度1 080 ℃、压下速度5 mm/s、最大压下量60%的热变形及固溶试验,结合EBSD大面积拼接技术的全域晶体学表征,研究截面整体晶粒演化规律。结果表明,热变形过程中GH4742晶粒尺寸演化由非连续动态再结晶主导,且与应变储能相关性较大,并受到析出相钉扎的抑制作用。当想钉扎力一定时,晶粒取向的不同导致再结晶驱动力存在差异,再结晶形核和长大呈现不均匀分布。由于析出相的钉扎作用及位错亚结构的均匀化,亚固溶处理过程中再结晶形核和长大过程受到抑制,仍存在较多变形晶粒。过固溶处理后晶粒尺寸分布均匀,平均晶粒尺寸为232 μm。

关键词: GH4742合金, 显微组织演化, 大面积拼接, 应变梯度, 动态再结晶

Abstract: The control of grain size plays an important role on metal materials to obtain excellent mechanical properties, especially for nickel-based superalloy with high content of precipitated phase. The interaction between precipitates and grains is complex in the process of recrystallization and grain growth during hot deformation and solution treatment. In addition, the traditional small sample hot compression simulation method can not meet the research needs. Taking GH4742 alloy as the research object, the whole grain evolution of cross section was studied through the hot deformation and solution tests of large size biconical samples at 1080 ℃, deformation speed of 5 mm/s and maximum reduction of 60 %, combined with the global crystal characterization of EBSD large area montage technology. The results show that the grain size evolution of GH4742 during hot deformation is dominated by discontinuous dynamic recrystallization, which is closely related to strain energy storage and is inhibited by precipitated phase pinning. When the pinning force is constant, the different grain orientation leads to the difference of recrystallization driving force, and the recrystallization nucleation and growth show non-uniform distribution. Due to the pinning effect of precipitated phase and the homogenization of dislocation substructure, the nucleation and growth of recrystallization are inhibited in the process of sub-solvu treatment, and there are still many deformed grains. After super-solvu treatment, the grain size distribution is uniform, and the average grain size is 232 μm.

Key words: GH4742 alloy, microstructure evolution, large area montage, strain gradient, dynamic recrystallization

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