M23C6 chromium-rich carbides are common grain-boundary precipitations in Cr-containing steel.The presence of grain-boundary carbides often leads to intergranular brittleness and decreases mechanical properties.This st...M23C6 chromium-rich carbides are common grain-boundary precipitations in Cr-containing steel.The presence of grain-boundary carbides often leads to intergranular brittleness and decreases mechanical properties.This study proposes a deformation and aging technique to obtain a high-volume-fraction dispersion distribution of the hard nano-M23C6 phase by changing the nucleation sites from grain boundaries to deformation coherent twin boundaries produced during cold deformation.The M23C6 precipitation-strengthened austenitic stainless steel has a strength of up to 1.4 GPa but maintains favorable plasticity(>11%).This study provides a novel approach for the control of intergranular brittleness in metallic materials.展开更多
Creep rupture of the reduced activation ferritic/martensitic(RAFM)steel and 316L steel dissimilar joint by friction stir welding was investigated.The creep rupture time of the dissimilar joint was 1941 h at 600℃/100 ...Creep rupture of the reduced activation ferritic/martensitic(RAFM)steel and 316L steel dissimilar joint by friction stir welding was investigated.The creep rupture time of the dissimilar joint was 1941 h at 600℃/100 MPa and 120 h at 650℃/100 MPa.The creep fracture occurred in heat affect zone(HAZ)of RAFM steel side where coarse Laves phase was detected.The formation and coarsening of the Laves phase particles in HAZ of RAFM steel side were the main reasons that caused the creep fracture of the dissimilar joint.The Laves phase particles nucleated adjacent to the large M_(23)C_(6) particles at the grain boundaries where W element segregated and grew fast during creep exposure.The large Laves phase would deteriorate the pinning effect of M_(23)C_(6) carbides and weaken the solid solution strengthening effect.Besides,the size of the Laves phase in HAZ of RAFM steel side was bigger than that in stir zone of RAFM steel side.These reasons explain the creep fracture in HAZ of RAFM steel side of dissimilar joint.展开更多
基金supported by the National Natural Science Foundation of China(No.52250130).
文摘M23C6 chromium-rich carbides are common grain-boundary precipitations in Cr-containing steel.The presence of grain-boundary carbides often leads to intergranular brittleness and decreases mechanical properties.This study proposes a deformation and aging technique to obtain a high-volume-fraction dispersion distribution of the hard nano-M23C6 phase by changing the nucleation sites from grain boundaries to deformation coherent twin boundaries produced during cold deformation.The M23C6 precipitation-strengthened austenitic stainless steel has a strength of up to 1.4 GPa but maintains favorable plasticity(>11%).This study provides a novel approach for the control of intergranular brittleness in metallic materials.
基金supported by the National Natural Science Foundation of China(52034004).
文摘Creep rupture of the reduced activation ferritic/martensitic(RAFM)steel and 316L steel dissimilar joint by friction stir welding was investigated.The creep rupture time of the dissimilar joint was 1941 h at 600℃/100 MPa and 120 h at 650℃/100 MPa.The creep fracture occurred in heat affect zone(HAZ)of RAFM steel side where coarse Laves phase was detected.The formation and coarsening of the Laves phase particles in HAZ of RAFM steel side were the main reasons that caused the creep fracture of the dissimilar joint.The Laves phase particles nucleated adjacent to the large M_(23)C_(6) particles at the grain boundaries where W element segregated and grew fast during creep exposure.The large Laves phase would deteriorate the pinning effect of M_(23)C_(6) carbides and weaken the solid solution strengthening effect.Besides,the size of the Laves phase in HAZ of RAFM steel side was bigger than that in stir zone of RAFM steel side.These reasons explain the creep fracture in HAZ of RAFM steel side of dissimilar joint.
