(1. 中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
2. 中南大學(xué) 航空航天學(xué)院，長(zhǎng)沙 410083；
3. 哈爾濱工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，哈爾濱 150001)
摘 要: 采用光學(xué)顯微鏡(OM)、掃描電鏡(SEM)、電子背散射衍射(EBSD)技術(shù)和透射電鏡(TEM)研究GH4169合金中δ相在高溫變形條件下的演變規(guī)律，分析δ相的溶解過(guò)程及其動(dòng)力學(xué)機(jī)制，探討δ相對(duì)GH4169合金高溫變形動(dòng)態(tài)再結(jié)晶機(jī)制的影響。結(jié)果表明：隨變形溫度的升高或應(yīng)變速率的降低δ相含量減少，動(dòng)態(tài)再結(jié)晶晶粒尺雨和體積含量增大，δ相主要以彎曲、扭折和切斷等方式來(lái)協(xié)調(diào)塑性變形，并在界面能降低的驅(qū)動(dòng)力下由針狀逐漸轉(zhuǎn)變?yōu)槎提槧钅酥燎驙睿辉诟邷刈冃螚l件下，δ相的溶解時(shí)間大大縮短，位錯(cuò)、空位和曲率對(duì)δ相的溶解起到重要作用，這主要與其對(duì)溶質(zhì)原子擴(kuò)散行為的影響有關(guān)，變形過(guò)程中產(chǎn)生的大量高密度位借及空位為溶質(zhì)原子提供了眾多高速率擴(kuò)散通道，促進(jìn)了δ相的溶解；δ相的存在改變了GH4169合金的動(dòng)態(tài)再結(jié)晶機(jī)制，其動(dòng)態(tài)再結(jié)晶機(jī)制主要有δ相誘發(fā)動(dòng)態(tài)再結(jié)晶形核和非連續(xù)動(dòng)態(tài)再結(jié)晶形核。
關(guān)鍵字: GH4169合金；δ相；溶解；動(dòng)態(tài)再結(jié)晶機(jī)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
