• CN:11-2187/TH
  • ISSN:0577-6686

›› 2011, Vol. 47 ›› Issue (6): 51-56.

• 论文 • 上一篇    下一篇

GH625合金热变形过程的动态再结晶行为研究

郭青苗;李德富;郭胜利;吾志岗;彭海健;胡捷   

  1. 有色金属研究总院
  • 发布日期:2011-03-20

Research on Dynamic Recrystallization Behavior of GH625Superalloy during Hot Deformation

GUO Qingmiao;LI Defu;GUO Shengli;WU Zhigang;PENG Haijian;HU Jie   

  1. General Research Institute for Non-ferrous Metals
  • Published:2011-03-20

摘要: 采用Gleeble-1500热模拟试验机,对GH625合金进行不同条件的热压缩试验以研究其热变形行为。利用光学显微镜(Optical microscope, OM)、背散射电子衍射(Electron backscatter diffraction, EBSD)和透射电镜(Transmission electron microscope, TEM)等手段,分析GH625合金在热变形过程中的组织演变及动态再结晶机制。研究结果表明,GH625合金在热变形过程中发生了动态再结晶,且根据变形温度的不同,真应力-真应变曲线的特征有所不同;GH625合金发生动态再结晶的临界应变与应力随着变形温度的升高而降低;GH625合金动态再结晶的晶粒尺寸及体积分数随着真应变的升高而升高,当合金完全动态再结晶后,动态再结晶晶粒的尺寸则随真应变的继续升高而基本保持不变;GH625合金的主要动态再结晶机制是在原始晶界凸起形核的不连续动态再结晶机制(Discontinuous dynamic recrystallization, DDRX),在原始晶界附近通过亚晶粗化、复合孪生形核的连续动态再结晶机制(Continuous dynamic recrystallization, CDRX)则起辅助作用。

关键词: GH625合金, 动态再结晶机制, 热变形, 组织演变

Abstract: Hot compression tests are conducted by using a Gleeble–1500 thermomechanical simulator to investigate the hot deformation behavior of GH625 superalloy. Optical microscope(OM), electron backscatter diffraction(EBSD) and transmission electron microscope(TEM) techniques are employed to analyze the microstructure evolution and nucleation mechamisms of dynamic recrystallization(DRX) in hot–deformed GH625 superalloy. It is found that the dynamic recrystallization process of GH625 alloy occurs during hot deformation, and the characteristics of the true stress-true strain curve are different when the deformation temperature is different. The critical strain and stress of the onset of DRX process increase with the rising of deformation temperature. The size and fraction of dynamically recrystallized grains increase with the increasing of strain. However, there is no change in the size of the DRX grains with the continuous increasing of strain when the microstructure fully completes dynamic recrystallization. A discontinuous dynamic recrystallization(DDRX) with nucleation mechanism of bulging of the original grain boundaries is the operating nucleation mechanism of DRX of Inconel 625 superalloy. A continuous dynamic recrystallization (CDRX) with subgrain rotation and formation of twinning in the vicinity of the serrated grain boundaries, which can only be considered as an assistant nucleation mechanism of DRX, occurring simultaneously with DDRX.

Key words: GH625 superalloy, Hot deformation, Mechanism of dynamic recrystallization, Microstructure evolution

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