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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M_(23)C_6相,晶内弥散析出细小的球形γ’相和针状M_(23)C_6。随时效时间延长,晶界M_(23)C_6长大并连接;晶内γ’相增多、长大,但仍十分细小;晶内M_(23)C_6逐渐长大为薄板状,同时不断析出新的、细小M_(23)C_6。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M_(23)C_6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M_(23)C_6的析出使硬度和强度上升,后因γ’相和M_(23)C_6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M_(23)C_6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。
The microstructures of Inconel 617B welded joints before and after 750 ℃ aging were studied to investigate the effect of microstructure evolution on hardness, strength and toughness during aging. The results show that after aging, a massive M 23 C 6 phase precipitates in the grain boundary of Inconel 617B, and fine spherical γ ’phase and acicular M 23 C 6 precipitate in the grain. With the aging time prolonging, the grain boundary M_ (23) C_6 grows and connects; the γ ’phase increases and grows up but still is very small in the grain; the M_ (23) C_6 in the grain gradually grows into thin plate shape, The small M_ (23) C_6. The changes of grain boundary and intragranular precipitates during the aging process of the weld zone are similar to those of the base metal, except that the M_ (23) C_6 precipitates are more distributed among the dendrites. The hardness and strength of Inconel 617B welded joints at 750 ℃ increased first and then decreased. The precipitation of γ ’phase and M_ (23) C_6 increased the hardness and strength at early aging stage, and then precipitated and elongated due to γ’ phase and M_ (23) C_6 phase Ambassador hardness and intensity showed a downward trend. The significant decrease of early aging toughness is related to the precipitated γ-phase of M_ (23) C_6 and the intragranular precipitation. With the aging time, Inconel 617B welded joints, hardness, strength and toughness decreased slowly.