Development of the high-strength ductile ferritic alloys via regulating the intragranular and grain boundary precipitation of G-phase

查看全文 作　　者：Mujin [1,2]Yang;Chao [1]Huang;Jiajia [3]Han;Haichen [4]Wu;Yilu [1]Zhao;Tao [5]Yang;Shenbao [6]Jin;Chenglei [1]Wang;Zhou [1]Li;Ruiying [6]Shu;Cuiping [3]Wang;Huanming [4]Lu;Gang [6]Sha;Xingjun [1,7,8]Liu 机构地区：[1]School of Materials Science and Engineering,Harbin Institute of Technology,Shenzhen 518055,China;[2]Department of Mechanical and Energy Engineering,Southern University of Science and Technology,Shenzhen 518055,China;[3]College of Materials and Fujian Provincial Key Laboratory of Materials Genome,Xiamen University,Xiamen 361005,China;[4]Test Center,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China;[5]Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong,China;[6]Department of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;[7]State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Shenzhen 150001,China;[8]Institute of Materials Genome and Big Data,Harbin Institute of Technology,Shenzhen 518055,China 出　　处：《Journal of Materials Science & Technology》索引2023年第5期,共20页 基　　金：This work was financially funded by the National Natural Science Foundation of China(Nos.51971082 and 52001098);the National Post-doctoral Program for Innovative Talents(No.BX20200103);the China Post-doctoral Science Foundation(No.2020M681092).The authors would like to thank Dr.Ivan Povstugar at ZEA-。 摘　　要：A typical G-phase strengthened ferritic model alloy(1Ti:Fe-20Cr-3Ni-1Ti-3Si,wt.%)has been carefully studied using both advanced experimental(EBSD,TEM and APT)and theoretical(DFT)techniques.During the classic“solid solution and aging”process,the superfine(Fe,Ni)_(2)TiSi-L2_(1)particles densely precipitate within the ferritic grain and subsequently transform into the(Ni,Fe)_(16)Ti_(6)Si_(7)-G phase.In the meanwhile,the elemental segregation at grain boundaries and the resulting precipitation of a large amount of the(Ni,Fe)_(16)Ti_(6)Si_(7)-G phase are also observed.These nanoscale microstructural evolutions result in a remarkable increase in hardness(100-300 HV)and severe embrittlement.When the“cold rolling and aging”process is used,the brittle fracture is effectively suppressed without loss of nano-precipitation strengthening ef-fect.Superhigh yield strength of 1700 MPa with 4%elongation at break is achieved.This key improvement in mechanical properties is mainly attributed to the pre-cold rolling process which effectively avoids the dense precipitation of the G-phase at the grain boundary.These findings could shed light on the further exploration of the precipitation site via optimal processing strategies. 关 键 词：G-phase Precipitation strengthening Grain boundary segregation Nano-precipitates