(中南大學(xué)航空航天學(xué)院，長沙 410083)
摘 要: 采用熱模擬試驗(yàn)機(jī)研究δ相時效態(tài)GH4169合金在變形溫度為980~1100 ℃、應(yīng)變速率為1×10-3~1s-1條件下的熱壓縮變形行為，繪制真應(yīng)力-真應(yīng)變曲線。結(jié)果表明：該合金在變形過程中出現(xiàn)了明顯的動態(tài)軟化行為。利用摩擦修正后的峰值應(yīng)力數(shù)據(jù)構(gòu)建了該合金的熱壓縮本構(gòu)方程，獲得了本構(gòu)方程材料常數(shù)分別為α=0.005626、n=4.2643、A=5.6185×1017、Q=486.8 kJ/mol。構(gòu)建了不同應(yīng)變量ε下合金本構(gòu)方程材料常數(shù)的五次多項(xiàng)式組，并根據(jù)多項(xiàng)式對其流變應(yīng)力進(jìn)行了預(yù)測。結(jié)果表明其預(yù)測數(shù)據(jù)與摩擦修正數(shù)據(jù)基本相符。利用動態(tài)材料模型方法建立了該合金在不同應(yīng)變量下的熱加工圖，分析了其在不同變形條件下的動態(tài)再結(jié)晶特性及流變失穩(wěn)行為。
關(guān)鍵字: GH4169合金；本構(gòu)方程；熱加工圖；動態(tài)再結(jié)晶；流變失穩(wěn)
（School of Aeronautics and Astronautics, Central South University, Changsha 410083, China）
Abstract:The hot compressive deformation behavior of delta-processed GH4169 alloy was investigated at temperature range of 980-1100 ℃ with strain rate from 1×10-3 to 1 s-1by thermal simulator. The true stress-true strain curves were obtained. The results show that the apparent dynamic softening behaviors occur during deformation. By using the friction-corrected peak stress data, the constitutive equation of the alloy for hot compression was established. The material constants are obtained to beα=0.005626, n=4.2643, A=5.6185×1017, Q=486.8 kJ/mol, respectively. A group of five-order polynomials showing the relationship between material constants of the constitutive equation and the strain was constructed, by which the flow stress was predicted. The predicted data are in good agreement with the friction-corrected one.According to the methods of dynamic material model, the hot processing maps of the alloy at different strains were established. The dynamic recrystallized characteristic under different deformation conditions and the flow instability behavior were also analyzed.
Key words: GH4169 alloy; constitutive equation; hot processing map; dynamic recrystallization; flow instability
