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采用Gleeble-1500热模拟实验机对Nimonic 80A高温合金进行了双道次热压缩实验,研究了该合金在变形温度1050~1150℃,应变速率0.01~2.5 s-1,预应变0.08~0.14,不同间隙时间(0.5~5 s)下的静态再结晶行为。得到了Nimonic 80A高温合金不同变形条件下的真应力-应变曲线及变形后奥氏体晶粒组织,分析了变形温度、应变速率和预应变对该合金静态再结晶行为的影响。结果表明:变形温度、应变速率和预应变对Nimonic 80A高温合金的静态再结晶行为有着显著的影响。Nimonic 80A高温合金静态软化分数随着变形温度、应变速率和预应变的增大而增大,且静态再结晶晶粒尺寸随着温度的升高或应变速率的降低而增大。根据实验结果,建立了Nimonic 80A高温合金静态再结晶动力学模型。将静态再结晶动力学模型预测结果和实验结果进行比较,二者吻合良好,表明本文提出的模型可以较为准确的预测Nimonic 80A高温合金静态软化行为。
A double-pass hot compression test was carried out on the Nimonic 80A superalloy using the Gleeble-1500 thermal simulation machine. The results show that the alloy has good mechanical properties at deformation temperature of 1050 ~ 1150 ℃, strain rate of 0.01 ~ 2.5 s-1, prestrain of 0.08 ~ 0.14, Static recrystallization behavior during gap time (0.5 ~ 5 s). The true stress-strain curve and austenite grain structure under different deformation conditions of Nimonic 80A superalloy were obtained. The effect of deformation temperature, strain rate and pre-strain on the static recrystallization behavior of the alloy was analyzed. The results show that deformation temperature, strain rate and pre-strain have a significant effect on the static recrystallization behavior of Nimonic 80A superalloy. The static softening fraction of Nimonic 80A superalloy increases with the deformation temperature, strain rate and prestrain, and the static recrystallization grain size increases with the increase of temperature or strain rate. According to the experimental results, the static recrystallization kinetics model of Nimonic 80A superalloy was established. The static recrystallization kinetics model prediction results and experimental results are compared, the two agree well, indicating that the model proposed in this paper can more accurately predict the static softening behavior of Nimonic 80A superalloy.