The interfacial microstructure evolution of 12Cr1MoV/TP347H dissimilar steel welded joints with a nickel-based filler metal during aging was studied in detail to elucidate the mechanism of premature failures of this kind of joints. The results showed that not only a band of granular Cr₂₃C₆ carbides were formed along the fusion boundary in the ferritic steel during aging, but also a large number of granular or platelike Cr₂₃C₆ carbides, which have a cube-cube orientation relationship with the matrix, were also precipitated on the weld metal side of the fusion boundary, making this zone be etched more easily than the other zone and become a dark etched band. Stacking faults were found in some Cr₂₃C₆ carbides. In the as-welded state, deformation twins were observed in the weld metal with a fully austenitic structure. The peak micro-hardness was shifted from the ferritic steel side to the weld metal side of the fusion boundary after aging and the peak value increased significantly. Based on the experimental results, a mechanism of premature failures of the joints was proposed.

详细研究了 12Cr1MoV/TP347H 异种钢镍基焊料焊接接头时效过程中的界面微观结构演变，阐明了此类接头过早失效的机理。结果表明,时效过程中,铁素体钢不仅沿熔合界面形成了条带状的Cr ₂₃ C ₆碳化物,而且还形成了大量具有立方体取向的粒状或板状的Cr ₂₃ C ₆碳化物。与基体的关系，也在熔合边界的焊缝金属侧析出，使该区域比其他区域更容易蚀刻并成为暗蚀刻带。在一些 Cr ₂₃ C中发现了堆垛层错₆碳化物。在焊接状态下，在具有完全奥氏体结构的焊缝金属中观察到变形孪晶。时效后显微硬度峰值从铁素体钢侧向熔合边界的焊缝金属侧移动，峰值显着增加。根据实验结果，提出了接头过早失效的机理。