【摘要】 研究Inconel 617B焊接接头750℃时效前后的组织,探讨时效过程中组织演变对硬度、强度和韧性的影响。结果表明:时效后,Inconel 617B晶界析出块状M₂₃C₆相,晶内弥散析出细小的球形γ’相和针状M₂₃C₆。随时效时间延长,晶界M₂₃C₆长大并连接;晶内γ’相增多、长大,但仍十分细小;晶内M₂₃C₆逐渐长大为薄板状,同时不断析出新的、细小M₂₃C₆。焊缝区时效过程中晶界和晶内析出相的变化与母材区类似,只是M₂₃C₆析出相更多分布在枝晶间。Inconel 617B焊接接头750℃时效硬度和强度先升后降,时效早期γ’相和M₂₃C₆的析出使硬度和强度上升,后因γ’相和M₂₃C₆相不断析出和长大使硬度和强度呈现下降趋势。时效早期韧性的显著下降则与晶界析出的M₂₃C₆和晶内析出的γ’相有关。随时效时间延长,Inconel 617B焊接接头的硬度、强度和韧性下降趋缓。更多还原

【Abstract】 Microstructure of Inconel 617 B welded joints before and after aging at 750 ℃ was investigated,and the effect of microstructural evolution on hardness,strength and impact toughness of the welded joints during aging was discussed.The results show that aging results in the precipitation of cuboid M₂₃C₆ at grain boundaries and dispersion precipitation of fine spherical γ’ particles and needle-like M₂₃C₆ particles in the grain interior.With the aging time increasing,M₂₃C₆ at grain boundaries becomes coarse and connected.γ’ continues to precipitate and grow up,but still keeps fine after long-term aging.Accompanied by the change of M₂₃C₆ from needles to plates,some fine needle-like M₂₃C₆ particles precipitate.The change of precipitates at grain boundaries and in grain interior in the weld metals during aging is similar to base metals,except that M₂₃C₆ precipitates in the interdendritic region rather than dendritic region.The precipitation of γ’and M₂₃C₆ results in the increase of hardness and strength in the early stage of aging,whereas the continual precipitation and coarsening ofγ’ and M₂₃C₆ may lead to the decrease of hardness and strength in the following aging process.The marked decline of impact toughness in the early stage of aging is related with the precipitation of M₂₃C₆ at grain boundaries and γ’ in grain interior.With the increase of aging time,the hardness,strength and impact toughness of the Inconel 617 B welded joints tend to be stable.更多还原