应变量对细晶Inconel 718高温合金热变形组织演变的影响  

Microstructure Evolution of Inconel 718 Superalloy with Fine-Grains at Different Strain during Hot Deformation

作　　者：李应隆 曾梦婷 谭元标 刘江梅 彭灿 王学爱 Li Yinglong;Zeng Mengting;Tan Yuanbiao;Liu Jiangmei;Peng Can;Wang Xueai(Guizhou Key Laboratory of Materials Mechanical Behaviour and Microstructure,College of Materials and Metallurgy,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学材料与冶金学院,贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《稀有金属》2023年第6期807-814,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51804087);贵阳市科技计划项目(筑科合同[2021]1-7号);贵州大学大学生创新创业训练计划项目(贵大(国)创字2021(036))资助。

摘　　要：研究了应变量对细晶Inconel 718高温合金热变形组织演变的影响。结果表明:真应变为0.2时,晶粒仅发生轻微变形,原始晶粒的晶界处局部位置有极少数新晶核形成,真应变达到0.4时,大量细小的再结晶晶核在变形晶粒晶界处形成。真应变为0.8时,再结晶程度达到峰值。随应变继续增大,晶粒发生粗化。热变形初期,合金的变形主要集中在晶界处,晶界处位错密度较高。真应变增加到0.6时,位错密度增加。随应变量进一步增加,晶粒内部的局部取向差(KAM)值明显降低,几何必须位错密度降低。当应变量为1.2时,由于变形过程中再结晶晶粒发生二次变形,合金中的位错密度仍保持在5.67×10^(14)m^(-2)。随真应变从0.2增加到0.8,再结晶体积分数从13.2%增加到了96%,而晶粒尺寸仅从4.94μm增加到7.26μm;当真应变从0.8增加到1.2,再结晶体积分数变化不大,而晶粒尺寸增加到了12.23μm,表明此变形阶段主要发生再结晶晶粒的长大。Inconel 718 superalloy is a precipitation-strengthened nickel-based superalloy with γ'-Ni_(3)(Al,Ti)andγ"-Ni_(3)Nb as reinforcing phases.Due to its good high temperature mechanical strength,toughness and excellent high temperature oxidation resistance and corrosion resistance above 600℃,it has been widely used in aerospace,nuclear power plant,gas turbine blade,combustion chamber,shaft and other key high temperature parts.With the development of aviation industry,the service conditions of aerospace equipment are increasingly severe and complex,which puts forward a higher requirements for the mechanical properties of aviation key components.The mechanical properties of the parts for the alloys and metals is depended on the microstructure formed during the hot working of the alloys and metals.In the process of hot processing,the strain distribution is generally asymmetrical,especially in the preparation of complex components,the dynamic recrystallization in the small deformation area is incomplete,and the subsequent high temperature isothermal process will further occur subdynamic recrystallization.The difference in true strain will result in a different microstructures,which can obtain a different mechanical properites.For Inconel 718 superalloy,the complex microstructure evolution can occur during the hot working process,which is closely related to the deformation process parameters,such as deformation temperature and true strain variables.Therefore,it is necessary to systematically study the microstructure evolution of Inconel 718 superalloy in the process of hot working,so as to guide the improvement of the mechanical properties of key alloy parts.In addition,the flow stress changes during the hot deformation processing is also closely related to its internal microstructure evolution.The flow stress behavior is a comprehensive reflection of work hardening,dynamic recovery softening,dynamic recrystallization,pass intermittent subdynamic recrystallization and static recrystallization in the process of hot proc

关 键 词：Inconel 718高温合金 热压缩变形 形核和长大 组织演变 

分 类 号：TG14[一般工业技术—材料科学与工程]