A new type-γ'/γ''coprecipitation behavior and its evolution mechanism in wrought Ni-based ATI 718Plus superalloy  

作　　者：Qianying Guo Zongqing Ma Zhixia Qiao Chong Li Teng Zhang Jun Li Chenxi Liu Yongchang Liu 

机构地区：[1]State Key Laboratory of Hydraulic Engineering Simulation and Safety,School of Materials Science and Engineering,Tianjin University,Tianjin 300354,China [2]School of Mechanical Engineering,Tianjin University of Commerce,Tianjin 300134,China [3]Southwestern institute of physics,Chengdu,Sichuan,610041,China

出　　处：《Journal of Materials Science & Technology》2022年第24期98-110,共13页材料科学技术（英文版）

基　　金：the National Natural Science Foundation of China(Nos.52034004,51974201 and 52122409)for grant and financial support。

摘　　要：In the precipitation-hardened Ni-based superalloy,typified by ATI 718 Plus,the nano-scaleγandγphase in duplet or triple coprecipitate morphology can provide superior high-temperature strength.Thus,it is of great sense to study the evolution ofγ’/γ’’coprecipitate during long term service at elevated temperature.In this study,the new-typeγ’/γ’’coprecipitates with a sandwich or compact configuration were found firstly in wrought ATI 718 Plus superalloy during long term thermal exposure at 705℃.These co-structure of theγ’/γ’’precipitates evidently inhibit the coarsening ofγ’phase.The increase of thermal exposure time evidently leads to the increase of the volume fraction ofγ’/γ’’coprecipitate and transformation of sandwich-typeγ’/γ’’coprecipitate to compact-typeγ’/γ’’coprecipitate,which is characterized asγphase precipitate at several faces of theγphase.The main evolution mechanism ofγ’/γ’’coprecipitates is element segregation,especially the composition variations of Al+Ti and Nb and their ratio of Al+Ti/Nb.In addition,the interfacial energy betweenγ’’phase andγmatrix also plays a key role on theγ’/γ’’coprecipitates evolution.The calculated results show that the longer thermal exposure time leads to the higher interfacial energy,which is beneficial for nucleation and precipitation ofγ’’phase on the faces ofγ’phase.

关 键 词：Wrought 718Plus superalloy γ’/γ’’coprecipitates Long-term thermal exposure Precipitate evolution 

分 类 号：TG132.3[一般工业技术—材料科学与工程]