(1. 中南大學(xué) 粉末冶金研究院，長(zhǎng)沙 410083；
2. 中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 浙江久立特材科技股份有限公司，湖州 313028)
摘 要: 為研究鍛態(tài)C-276鎳基合金的熱變形行為，采用Gleeble-3180D熱模擬試驗(yàn)機(jī)對(duì)該合金在變形溫度950~1200 ℃以及應(yīng)變速率0.01~10 s-1條件下進(jìn)行一系列熱壓縮實(shí)驗(yàn)。結(jié)果表明，合金的流變應(yīng)力曲線都呈現(xiàn)明顯的動(dòng)態(tài)再結(jié)晶特征，并且流變應(yīng)力隨變形溫度的提升或者應(yīng)變速率的下降而降低。根據(jù)Arrhenius模型構(gòu)建該合金峰值應(yīng)力下的本構(gòu)方程，得出合金的變形激活能為510.484 kJ/mol。依據(jù)材料動(dòng)態(tài)模型繪制合金在0.6應(yīng)變下的熱加工圖，并結(jié)合組織分析提出該合金最優(yōu)的熱加工參數(shù)為(1100 ℃，0.01 s-1)以及(1150 ℃，0.01~1 s-1)。另外，合金的組織變化規(guī)律表明，溫度的增加或應(yīng)變速率的降低能夠促進(jìn)合金的動(dòng)態(tài)再結(jié)晶晶粒的形核與長(zhǎng)大。
關(guān)鍵字: C-276鎳基合金；熱變形；本構(gòu)方程；熱加工圖
（1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
2. State Key Laboratory of Powder Metallurgy Central South University, Changsha 410083, China;
3. Zhejiang Jiuli Hi-tech Metals Co., Ltd., Huzhou 313028, China）
Abstract:In order to investigate the hot deformation behavior of a forged C-276 nickel-based alloy, a series of hot compression tests at temperatures of 950-1200 ℃ and strain rates of 0.01-10 s-1 were carried out by Gleeble-3180D thermal simulator. The results show that the flow stress curves of alloy exhibite typical dynamic recrystallization characteristics and the flow stress decreases with the deformation temperature increasing or the strain rate reducing. Constitutive equation of C-276 alloy is constructed using peak stress according to Arrhenius model, and the deformation activation energy is 510.484 kJ/mol. At the strain of 0.6, a processing map is established based on dynamic material model. Combining with microstructure analysis, the optimum hot working parameters of C-276 alloy are (1100 ℃, 0.01 s-1) and (1150 ℃, 0.01-1 s-1). In addition, the microstructural change law of alloy indicates that the increase of deformation temperature or the reduce of strain rate can facilitate the nucleation and growth of dynamic recrystallization grain.
Key words: C-276 nickel-based alloy; hot deformation; constitutive equation; processing map
