Stress-state dependence of dynamic strain aging:Thermal hardening and blue brittleness  

作　　者：Wen-qi Liu Jun-he Lian 

机构地区：[1]Advanced Manufacturing and Materials,Department of Mechanical Engineering,Aalto University,Puumiehenkuja 3,02150 Espoo,Finland [2]Impact and Crashworthiness Lab,Department of Mechanical Engineering,Massachusetts Institute of Technology,77 Massachusetts Avenue,Cambridge,MA 02139-4307,USA

出　　处：《International Journal of Minerals,Metallurgy and Materials》2021年第5期854-866,共13页矿物冶金与材料学报（英文版）

基　　金：The authors gratefully acknowledge the valuable comments by Prof.Sebastian Münstermann from Steel Institute(IEHK),RWTH Aachen University,Germany.The work has been supported by the European Commission Research Fund for Coal and Steel(No.709711).Wenqi Liu is grateful to Shujing Li and Guangming Zeng from IEHK for data processing.

摘　　要：This study aims to discover the stress-state dependence of the dynamic strain aging(DSA)effect on the deformation and fracture behavior of high-strength dual-phase(DP)steel at different deformation temperatures(25-400°C)and reveal the damage mechanisms under these various configurations.To achieve different stress states,predesigned specimens with different geometric features were used.Scanning electron microscopy was applied to analyze the fracture modes(e.g.,dimple or shear mode)and underlying damage mechanism of the investigated material.DSA is present in this DP steel,showing the Portevin-Le Chatelier(PLC)effect with serrated flow behavior,thermal hardening,and blue brittleness phenomena.Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness.Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness.Accordingly,the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect.

关 键 词：dynamic strain aging effect Portevin-Le Chatelier effect damage mechanism dimple fracture shear fracture dual-phase steel 

分 类 号：TG142.1[一般工业技术—材料科学与工程]