The effect of long-term thermal exposure on the tensile behavior of a high W content nickel-based superalloy K416B was investigated. The microstructure and the deformation characteristics were observed by scanning electron microscopy and transmission electron microscopy, and the phase transformation of the alloy during long-term thermal exposure was analyzed by X-ray diffraction patterns and differential thermal analysis. Results showed that after thermal exposure at 1000 °C, the MC carbides in the K416B alloy decomposed into M₆C. During tensile deformation, dislocations slipping in γ matrix crossed over the M₆C by Orowan bowing mechanism. With the increase of thermal exposure time, the secondary M₆C reduced greatly the yield strength of the alloy at room temperature. Meanwhile, the continuous distribution of the secondary M₆C with great brittleness in the grain boundary could become the main source of crack, which might change the fracture characteristic of the alloy from trans-granular to intergranular.

研究了长期热暴露对高W含量镍基高温合金K416B的拉伸行为的影响。通过扫描电子显微镜和透射电子显微镜观察其微观结构和变形特性，并通过X射线衍射图和差热分析分析合金在长期热暴露期间的相变。结果表明，在1000热暴露后℃时，中号的K416B合金C碳化物分解成中号₆ ℃。在拉伸变形，位错在滑移γ越过矩阵中号₆由奥罗万弯曲机构C。随着热暴露时间的增加，二次M ₆ C在室温下大大降低了合金的屈服强度。同时，具有较大脆性的次生M ₆ C的连续分布可能成为裂纹的主要来源，这可能会使合金的断裂特性从晶间转变为晶间。