(1. 中南大学 粉末冶金国家重点实验室，长沙 410083；
2. 中南大学 航空航天学院，长沙 410083；
3. 哈尔滨工业大学 材料科学与工程学院，哈尔滨 150001)
摘 要: 采用光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)技术和透射电镜(TEM)研究GH4169合金中δ相在高温变形条件下的演变规律，分析δ相的溶解过程及其动力学机制，探讨δ相对GH4169合金高温变形动态再结晶机制的影响。结果表明：随变形温度的升高或应变速率的降低δ相含量减少，动态再结晶晶粒尺雨和体积含量增大，δ相主要以弯曲、扭折和切断等方式来协调塑性变形，并在界面能降低的驱动力下由针状逐渐转变为短针状乃至球状；在高温变形条件下，δ相的溶解时间大大缩短，位错、空位和曲率对δ相的溶解起到重要作用，这主要与其对溶质原子扩散行为的影响有关，变形过程中产生的大量高密度位借及空位为溶质原子提供了众多高速率扩散通道，促进了δ相的溶解；δ相的存在改变了GH4169合金的动态再结晶机制，其动态再结晶机制主要有δ相诱发动态再结晶形核和非连续动态再结晶形核。
关键字: GH4169合金；δ相；溶解；动态再结晶机制
deformation mechanism of GH4169 alloy
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Aeronautics and Astronautics, Central South University, Changsha 410083, China;
3. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The evolution of δ phase during hot deformation of GH4169 alloy was investigated by optical microscopy (OM), electron backscattering diffractometry (EBSD), scanning and transmitting electron microscopy. The dissolution processes of δ phase and dynamic mechanisms were analyzed. The effect of δ phase on the mechanism of dynamic recrystallization (DRX) was discussed. The results show that, with increasing deformation temperature and decreasing strain rate, the content of δ phase decreases, but the grain size and volume fraction for dynamic recrystallization increase. The plastic deformation is mainly accommodated by bending, kinking and shearing of δ phase. Under the drive force of reduced interface energy, δ phase is transformed from needle to short needle and even sphere. The accelerated dissolution of δ phase can be attributed to the effect of dislocation, vacancy and curvature, which is concerned with the diffusion behavior of solute atoms. A larger amount of high-speed channels for the diffusion of solute atoms form due to the existence of massive defects, such as high density dislocations and vacancies, promoting the dissolution of δ phase. The main nucleation mechanisms of DRX are changed to be δ phase stimulated nucleation and discontinuous nucleation due to δ phase.
Key words: GH4169 alloy; δ phase; dissolution; dynamic recrystallization mechanism
