Unraveling the significance of cobalt on transformation kinetics,crystallography and impact toughness in high-strength steels  

作　　者：Yishuang Yu Jingxiao Zhao Xuelin Wang Hui Guo Zhenjia Xie Chengjia Shang 

机构地区：[1]Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China [2]School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [3]State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第2期380-390,共11页矿物冶金与材料学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52271089);the financial support from the C hina Postdoctoral Science Foundation(No.2023M732192)。

摘　　要：This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co.Moreover,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6.The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant pair.Furthermore,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant pair.These findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.

关 键 词：high-strength steel COBALT transformation kinetics CRYSTALLOGRAPHY impact toughness 

分 类 号：TG142[一般工业技术—材料科学与工程]