(1. 中南大學 粉末冶金國家重點實驗室，長沙 410083；
2. 中南大學 航空航天學院，長沙 410083)
摘 要: 通過熱模擬試驗，系統(tǒng)研究熱擠壓-退火態(tài)FGH96合金在變形溫度為1020~1110 ℃、應(yīng)變速率為0.001~1 s-1條件下的熱壓縮變形行為，建立本構(gòu)方程并構(gòu)建熱加工圖；結(jié)合電子背散射衍射(EBSD)分析，優(yōu)化合金的變形工藝參數(shù)。結(jié)果表明：合金在熱變形過程中發(fā)生明顯動態(tài)再結(jié)晶現(xiàn)象。利用摩擦修正后的峰值應(yīng)力獲得的該合金熱壓縮本構(gòu)方程材料常數(shù)分別為：α=0.0071272、n=2.6417、A=6.6811×1015、Q=448.05 kJ/mol，較低的變形激活能與熱擠壓后初始晶粒尺寸的減小以及二次γ′相的粗化有關(guān)。利用構(gòu)建的不同應(yīng)變量ε下熱壓縮本構(gòu)方程材料常數(shù)的五次多項式組對合金的流變應(yīng)力進行了預(yù)測，預(yù)測數(shù)據(jù)與實驗?zāi)Σ列拚龜?shù)據(jù)吻合較好。根據(jù)熱加工圖能量耗散效率并結(jié)合微觀組織分析，對熱擠壓-退火態(tài)FGH96合金提出了建議的熱加工參數(shù)范圍：變形溫度約為1075~1080 ℃、應(yīng)變速率約為1×10-3~1×10-1.5 s-1的區(qū)域。
關(guān)鍵字: FGH96合金；熱壓縮變形；本構(gòu)方程；變形激活能；熱加工圖
（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）
Abstract:Hot compressive deformation behavior of as hot extruded-annealed FGH96 alloy was systematically investigated at the temperatures from 1020 ℃ to 1110 ℃ with strain rates from 1×10-3 to 1 s-1 by thermal simulation experiments. The constitutive equation for hot compression of the alloy was established, and the hot processing map was also constructed. Combined with electron backscatter diffraction (EBSD) analysis, the deformation parameters of the alloy were optimized. The results show that apparent dynamic recrystallization occurs during hot deformation of the alloy. By using the friction-corrected peak stress data, the material constants of the constitutive equation for hot compression of the alloy are obtained to be α=0.0071272, n=2.6417, A=6.6811×1015, Q=448.05 kJ/mol, respectively. The lower activation energy of deformation is closely related to the decrease of initial grain size after hot extrusion and the coarsening of secondary γ′ precipitate. A group of five-order polynomials showing the relationship between material constants of the constitutive equation and strain is built up, by which the flow stresses are predicted. The predicted data are in good agreement with the experimental friction-corrected one. Considering the energy dissipation efficiency in the hot processing map and the microstructural analysis, the hot working parameters of the as hot extruded-annealed FGH96 alloy are suggested to be the deformation temperatures of about 1075-1080 ℃ and the strain rate of about 1×10-3-1×10-1.5 s-1.
Key words: FGH96 alloy; hot compression deformation; constitutive equation; deformation activation energy; hot processing map
