The change in dislocation configuration ahead of a loaded crack tip before and after charging with hydrogen was in situ investigated in TEM using a special constant deflection loading device The results showed that hy...The change in dislocation configuration ahead of a loaded crack tip before and after charging with hydrogen was in situ investigated in TEM using a special constant deflection loading device The results showed that hydrogen could facilitate dislocation emission, multiplication and motion The change in displacement field ahead of a loaded notch tip for a bulk specimen before and after charging with hydrogen was in situ measured by the laser moire interferometer technique. The results showed that hydrogen could enlarge the plastic zone and increase the plastic strain The in situ observation in TEM showed that when hydrogen-enhanced dislocation emission and motion reached a critical condition, a nanocrack of hydrogen-induced cracking ( HIC) would nucleate in the dislocation-free zone (DFZ) or at the main crack tip. The reasons for hydrogen-enhanced dislocation emission, multiplication and motion, and the mechanisms of nucleation of HIC have been discussed展开更多
Micropillar compression tests were used to investigate the influence of hydrogen on the deformation behavior and hydrogen embrittlement(HE)of nitrogen-alloyed austenitic stainless steel QN_(2)109.Results indicate that...Micropillar compression tests were used to investigate the influence of hydrogen on the deformation behavior and hydrogen embrittlement(HE)of nitrogen-alloyed austenitic stainless steel QN_(2)109.Results indicate that the hydrogen increases the dislocation density,reduces the yield stress,and accelerates the formation and intersection of slip bands,with hydrogen-induced cracks initiating at slip band intersections.X-ray diffraction confirms the absence of martensitic transformation,ruling out the role of martensitic transformation in HE.The micropillar compression technique is highly sensitive for characterizing hydrogen-material interactions,owing to the material’s low hydrogen diffusivity and the small size of its hydrogen-affected zone.These findings align with the hydrogen-enhanced localized plasticity mechanism.展开更多
Hydrogen embrittlement(HE)remains a critical challenge in the reliability and safety of metallic components across a range of engineering applications,from aerospace to energy infrastructure.This review comprehensivel...Hydrogen embrittlement(HE)remains a critical challenge in the reliability and safety of metallic components across a range of engineering applications,from aerospace to energy infrastructure.This review comprehensively explores the fundamental mechanisms underlying HE-including hydrogen-enhanced decohesion(HEDE),hydrogen-enhanced localized plasticity(HELP),and hydride-induced embrittlement-across various metal systems.Emphasis is placed on advanced characterization techniques such as thermal desorption spectroscopy,atom probe tomography,and in-situ mechanical testing,which provide multi-scale insights into hydrogen transport,trapping,and damage evolution.The study further evaluates key factors influencing HE susceptibility,including alloy composition,microstructural features,environmental conditions,and applied stress states.Mitigation strategies are systematically discussed,focusing on alloy design,microstructural engineering,surface treatments,and thermal processing.By integrating mechanistic understanding with practical prevention methods,this work provides a comprehensive framework for the design and maintenance of hydrogen-tolerant metallic materials in modern engineering systems.展开更多
基金Project supported by the National Natural Science Foundation of China and the State Key Laboratory of Corrosion and Protection of Metal.
文摘The change in dislocation configuration ahead of a loaded crack tip before and after charging with hydrogen was in situ investigated in TEM using a special constant deflection loading device The results showed that hydrogen could facilitate dislocation emission, multiplication and motion The change in displacement field ahead of a loaded notch tip for a bulk specimen before and after charging with hydrogen was in situ measured by the laser moire interferometer technique. The results showed that hydrogen could enlarge the plastic zone and increase the plastic strain The in situ observation in TEM showed that when hydrogen-enhanced dislocation emission and motion reached a critical condition, a nanocrack of hydrogen-induced cracking ( HIC) would nucleate in the dislocation-free zone (DFZ) or at the main crack tip. The reasons for hydrogen-enhanced dislocation emission, multiplication and motion, and the mechanisms of nucleation of HIC have been discussed
基金support from the National Natural Science Foundation of China(Grant No.U24A20105 and 52071209)the Major Scientific and Technological Innovation Project of CITIC Group(Grant No.2022ZXKYA06100,with Hongzhou Lu as the principal grant recipient)the Program of Shanghai Academic and Technology Research Leader(Grant No.18XD1402200).
文摘Micropillar compression tests were used to investigate the influence of hydrogen on the deformation behavior and hydrogen embrittlement(HE)of nitrogen-alloyed austenitic stainless steel QN_(2)109.Results indicate that the hydrogen increases the dislocation density,reduces the yield stress,and accelerates the formation and intersection of slip bands,with hydrogen-induced cracks initiating at slip band intersections.X-ray diffraction confirms the absence of martensitic transformation,ruling out the role of martensitic transformation in HE.The micropillar compression technique is highly sensitive for characterizing hydrogen-material interactions,owing to the material’s low hydrogen diffusivity and the small size of its hydrogen-affected zone.These findings align with the hydrogen-enhanced localized plasticity mechanism.
文摘Hydrogen embrittlement(HE)remains a critical challenge in the reliability and safety of metallic components across a range of engineering applications,from aerospace to energy infrastructure.This review comprehensively explores the fundamental mechanisms underlying HE-including hydrogen-enhanced decohesion(HEDE),hydrogen-enhanced localized plasticity(HELP),and hydride-induced embrittlement-across various metal systems.Emphasis is placed on advanced characterization techniques such as thermal desorption spectroscopy,atom probe tomography,and in-situ mechanical testing,which provide multi-scale insights into hydrogen transport,trapping,and damage evolution.The study further evaluates key factors influencing HE susceptibility,including alloy composition,microstructural features,environmental conditions,and applied stress states.Mitigation strategies are systematically discussed,focusing on alloy design,microstructural engineering,surface treatments,and thermal processing.By integrating mechanistic understanding with practical prevention methods,this work provides a comprehensive framework for the design and maintenance of hydrogen-tolerant metallic materials in modern engineering systems.
