Reconfiguring dual-phase structure with equal micro-hardness to achieve double strength with slight ductility sacrifice  

作　　者：Xuebing Liu Mengcheng Zhou Xinfang Zhang 

机构地区：[1]School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 10083,China

出　　处：《Journal of Materials Science & Technology》2023年第10期171-183,共13页材料科学技术（英文版）

基　　金：supported by the National Natural Sci-ence Foundation of China(Nos.U21B2082,51874023,U1860206);the Beijing Municipal Natural Science Foundation(No.2222065);the Nation Key Research and Development Program of China(No.2019YFC1908403);the Fundamental Research Funds for the Central Universities(No.FRF-TP-22-02C2).

摘　　要：The application of duplex stainless steel is severely restricted owing to its inherently low yield strength.A high yield strength of duplex stainless steel is required to address the lightweight issues and re-duce the emission of polluting gasses.Herein,excellent mechanical properties of duplex stainless steel were achieved using a flash annealing treatment to obtain austenite and ferrite phases with equal hard-ness,and the yield strength doubled without a substantial ductility sacrifice.The improvement in yield strength was caused by the grain boundary strengthening(a contribution of 60%to the yield strength)and hetero-deformation-induced strengthening(remaining 40%contribution to the yield strength)owing to the significant difference in the strain partitioning between the two phases.The high strain-hardening capability ensured ductility without a significant decrease;this correlated to the multiple microstruc-ture deformation mechanisms.These mechanisms included the synergetic deformation of the ferrite with dislocation cell formation and austenite accompanied by the sequential appearance of dislocation accumulation,stacking faults,and deformation-induced nanoscale twins and martensite.Deformation-induced multilevel stacking fault networks and high-density Lomer-Cotterll locks further improved the strain hardening response by enhancing the hetero-deformation behavior of austenite and ferrite.

关 键 词：Duplex stainless steel Flash annealing Equal hardness Strain partitioning Hetero-deformation 

分 类 号：TG142.1[一般工业技术—材料科学与工程]