Methods and mechanisms for uniformly refining deformed mixed and coarse grains inside a solution-treated Ni-based superalloy by two-stage heat treatment

作     者：Guan-Qiang Wang Ming-Song Chen Hong-Bin Li Y.C.Lin Wei-Dong Zeng Yan-Yong Ma Guan-Qiang Wang;Ming-Song Chen;Hong-Bin Li;Y.C.Lin;Wei-Dong Zeng;Yan-Yong Ma

作者机构：School of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Light Alloy Research InstituteCentral South UniversityChangsha 410083China State Key Laboratory of High Performance Complex ManufacturingChangsha 410083China College of Metallurgies and EnergyNorth China University Science and TechnologyTangshan 063009China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2021年第77卷第18期

页      面：47-57页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：the National Natural Science Foundation of China(No.51975593) the Hunan Provincial Natural Science Foundation of China(No.2020JJ4113) the Science and Technology Innovation Planning Project of Hunan Province(No.2019XK2301) 

主　　题：Ni-based superalloy Aging annealing Recrystallization annealing Grain refinement Microstructural evolution Mixed grain microstructure 

摘      要：The uniform refinement mechanisms and methods of deformed mixed and coarse grains inside a solution-treatment Ni-based superalloy during two-stage annealing treatment have been *** two-stage heat treatment experiments include an aging annealing treatment(AT)and a subsequent recrystallization annealing treatment(RT).The object of AT is to precipitate someδphases and consume part of storage energy to inhibit the grain growth during RT,while the RT is to refine mixed and coarse grains by *** can be found that the recrystallization grains will quickly grow up to a large size when the AT time is too low or the RT temperature is too high,while the deformed coarse grains cannot be eliminated when the AT time is too long or the RT temperature is too *** addition,the mixed microstructure composed of some abnormal coarse recrystallization grains(ACRGs)and a large number of fine grains can be observed in the annealed specimen when the AT time is 3 h and RT temperature is 980℃.The phenomenon attributes to the uneven distribution ofδphase resulted from the heterogeneous deformation energy when the AT time is too *** the regions with a large number ofδphases,the recrystallization nucleation rate is promoted and the growth of grains is limited,which results in fine ***,in the regions with fewδphases,the recrystallization grains around grain boundaries can easily grow up,and the new recrystallization nucleus is difficult to form inside grain,which leads to ***,in order to obtain uniform and fine annealed microstructure,it is a prerequisite to precipitate even-distributedδphase by choosing a suitable AT time,such as 12 ***,a relative high RT temperature is also needed to promote the recrystallization nucleation aroundδ*** optimal annealing parameters range for uniformly refining mixed crystal can be summarized as:900℃×12 h+990℃×(40-60 min)and 900℃×12 h+1000℃×(10-15 min).