Hydrogen embrittlement(HE)poses a significant challenge for the development of high-strength metallic materials.However,explanations for the observed HE phenomena are still under debate.To shed light on this issue,her...Hydrogen embrittlement(HE)poses a significant challenge for the development of high-strength metallic materials.However,explanations for the observed HE phenomena are still under debate.To shed light on this issue,here we investigated the hydrogen-defect interaction by comparing the dislocation structure evolution after hydrogen adsorption and desorption in a Fe-28Mn-0.3C(wt%)twinning-induced plasticity steel with an austenitic structure using in situ electron channeling contrast imaging.The results indicate that hydrogen can strongly affect dislocation activities.In detail,hydrogen can promote the formation of stacking faults with a long dissociation distance.Besides,dislocation movements are frequently observed during hydrogen desorption.The required resolved shear stress is considered to be the residual stresses rendered by hydrogen segregation.Furthermore,the microstructural heterogeneity could lead to the discrepancy of dislocation activities even within the same materials.展开更多
High temperature in diffusion bonding(DB)process severely deteriorates the performance of zirconium(Zr)R60702 in extreme chemical environment.Therefore,it is important to reduce the DB temperature of Zr R60702.In this...High temperature in diffusion bonding(DB)process severely deteriorates the performance of zirconium(Zr)R60702 in extreme chemical environment.Therefore,it is important to reduce the DB temperature of Zr R60702.In this work,low-temperature diffusion bonding of Zr R60702 at 750°C is realized by 0.3 wt%hydrogen addition while 900°C is required in DB process for unhydrogenated Zr R60702.The shear strength of the hydrogenated joint bonded at 750°C reaches 388 MPa,which is 117.98%higher than that of the unhydrogenated joint bonded at 750°C and equal to that of the unhydrogenated joint bonded at 900°C.The effects of hydrogen addition in Zr R60702 on the microstructure evolution,phase transformation temperature,interatomic bonding and self-diffusion coefficient of Zr atoms are investigated in detail.The results show that the optimized DB properties can be attributed to the improvements of its grain boundary diffusion,plasticity and self-diffusion coefficient of Zr atoms.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.52101022)the Shaanxi Province Natural Science Foundation(No.2021JQ-080).
文摘Hydrogen embrittlement(HE)poses a significant challenge for the development of high-strength metallic materials.However,explanations for the observed HE phenomena are still under debate.To shed light on this issue,here we investigated the hydrogen-defect interaction by comparing the dislocation structure evolution after hydrogen adsorption and desorption in a Fe-28Mn-0.3C(wt%)twinning-induced plasticity steel with an austenitic structure using in situ electron channeling contrast imaging.The results indicate that hydrogen can strongly affect dislocation activities.In detail,hydrogen can promote the formation of stacking faults with a long dissociation distance.Besides,dislocation movements are frequently observed during hydrogen desorption.The required resolved shear stress is considered to be the residual stresses rendered by hydrogen segregation.Furthermore,the microstructural heterogeneity could lead to the discrepancy of dislocation activities even within the same materials.
基金supported by the NSFC-Liaoning Province United Foundation(U1908229)the National Natural Science Foundation of China(51875350)the Program of Shanghai Academic Research Leader(22XD1421600).
文摘High temperature in diffusion bonding(DB)process severely deteriorates the performance of zirconium(Zr)R60702 in extreme chemical environment.Therefore,it is important to reduce the DB temperature of Zr R60702.In this work,low-temperature diffusion bonding of Zr R60702 at 750°C is realized by 0.3 wt%hydrogen addition while 900°C is required in DB process for unhydrogenated Zr R60702.The shear strength of the hydrogenated joint bonded at 750°C reaches 388 MPa,which is 117.98%higher than that of the unhydrogenated joint bonded at 750°C and equal to that of the unhydrogenated joint bonded at 900°C.The effects of hydrogen addition in Zr R60702 on the microstructure evolution,phase transformation temperature,interatomic bonding and self-diffusion coefficient of Zr atoms are investigated in detail.The results show that the optimized DB properties can be attributed to the improvements of its grain boundary diffusion,plasticity and self-diffusion coefficient of Zr atoms.
