GH4720Li合金粗晶组织热变形细化预测研究  

Refinement Prediction of Coarse-grained Structure of GH4720Li Alloy by Thermal Deformation

作　　者：沙磊 孙杰 赵张龙[2] 韦康 王涛 万志鹏 SHA Lei;SUN Jie;ZHAO Zhang-long;WEI Kang;WANG Tao;WAN Zhi-peng(College of Aeronautical,Changji University,Xinjiang Changji 831100,China;School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China;Laboratory of Science and Technology on Advanced High Temperature Structural Materials,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]昌吉学院航空学院,新疆昌吉831100 [2]西北工业大学材料学院,西安710072 [3]中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095

出　　处：《精密成形工程》2023年第6期146-154,共9页Journal of Netshape Forming Engineering

基　　金：新疆维吾尔自治区高等学校科学研究计划(XJEDU2022P115);镍钴资源综合利用国家重点实验室开放课题(GZSYS-KY-2022-019);先进高温结构材料国防科技重点实验室(6142903200206)。

摘　　要：目的研究不同变形参数下GH4720Li合金动态再结晶行为,建立GH4720Li合金粗晶组织动态再结晶细化的预测模型,为铸态初轧GH4720Li合金锻造工艺参数制定、粗晶组织消除、细晶组织获得提供理论支撑。方法在温度为1030~1150℃、应变速率为0.01~10 s^(-1)条件下,对铸态初轧GH4720Li合金粗晶组织进行了热压缩实验,分析了不同变形参数下合金的动态再结晶行为。研究了合金动态再结晶演化机制,构建了GH4720Li合金粗晶组织动态再结晶预测模型和晶粒尺寸模型,并结合实验对模型的准确性进行了验证。结果在合金热压缩过程中,流变应力表现出明显的加工硬化、动态回复和动态再结晶软化平衡特征,粗晶组织动态再结晶细化程度可以通过流变应力变化间接反映。根据应力-应变数据计算得到合金的热变形激活能为1230.48 kJ/mol,确定了Z参数与峰值应变和临界应变之间的关系,发现峰值应变和临界应变与Z参数均呈线性关系。通过观察合金微观组织发现,在变形过程中发生了非连续动态再结晶和连续动态再结晶,2种变形机制共同影响着粗晶组织的演化,所建立的动态再结晶细化模型和动态再结晶晶粒尺寸模型与实验值最大相对误差仅为8.5%和8.9%。结论所建模型的预测结果与实验结果基本一致,模型预测值具有较高的准确性,可以利用所建模型对合金动态再结晶细化进行定量预测。The work aims to study the dynamic recrystallization behavior of GH4720Li alloy under different deformation parameters,and establish the prediction model of dynamic recrystallization refinement of the coarse-grained structure of GH4720Li alloy,so as to provide theoretical support for formulating the forging process parameters of as-cast blooming GH4720Li alloy,eliminating the coarse-grained structure and obtaining the fine-grained structure.The thermal compression experiment was carried out to the coarse-grained structure of as-cast blooming GH4720Li alloy at a temperature of 1030-1150℃,and a strain rate of 0.01-10 s^(-1),and the dynamic recrystallization behavior of the alloy under different deformation parameters was analyzed.The dynamic recrystallization evolution mechanism of the alloy was studied,the dynamic recrystallization prediction model and grain size model of the alloy were established,and the experiments were conducted to verify the accuracy of the model.In the thermal compression of alloy,the flow stress led to evident work hardening,dynamic recovery and dynamic recrystallization softening equilibrium characteristics,and the change of flow stress could indirectly reflect the dynamic recrystallization refinement degree of coarse-grained structure.According to the stress-strain data,the activation energy Q of thermal deformation of the alloy was calculated to be 1230.48 kJ/mol,and the relationship between Z parameters andεp andεc was found to be linear.The DDRX and CDRX occurred during the deformation process through the observation on the alloy microstructure.The two deformation mechanisms jointly affected the evolution of coarse-grained structure.The maximum relative errors between the predicted value and the actual value of the dynamic recrystallization refinement model and the dynamic recrystallization grain size model were only 8.5%and 8.9%.The predicted results of the model are consistent with the experimental results,and the predicted values have high accuracy.Therefore,the proposed model c

关 键 词：GH4720Li粗晶组织 热变形 动态再结晶预测模型 晶粒尺寸模型 微观组织 

分 类 号：TG319[金属学及工艺—金属压力加工]