Zhao Hongchang, Han Xi, Wang Mingjia, Wang Zixi
Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China.
Department of Chemical Engineering and Modern Material, Shangluo University, Shangluo 726000, China.
Materials (Basel). 2022 May 20;15(10):3659. doi: 10.3390/ma15103659.
This paper focused on the microstructure evolution under different thermal aging times at 650 °C and its effect on creep behavior in 11Cr-3W-3Co heat-resistant steel. After short-term thermal aging at 650 °C (>750 h), a Laves phase was found in the regions adjacent to the PAG boundaries, martensitic lath boundaries, and M23C6 carbides, and gradually swallowed adjacent M23C6 carbides with the aging time increased. Higher contents of Si and P are good promoters of the nucleation of the Laves phase during long-term aging. In addition, the coarsening behavior of the Laves phase, M23C6, and MX were investigated. As the aging time increases, the coarsening behavior among precipitated phases in the above-mentioned example exhibits remarkable variability, which is discussed in detail in this paper, and the evolution of the subgrain size was also analyzed in detail. The increasing rate of subgrain size is, in general, consistent with that of the M23C6 carbide size. The evolution of dislocation density in different aging times shows an obvious difference, and the decreasing rate of dislocation density is significantly affected by the precipitated phase after long-term aging time. The creep performance of the material decreases significantly as the aging time increases, which is closely related to the coarsening of the precipitates such as M23C6 carbides and subgrain during long-term aging.
本文聚焦于650°C下不同热时效时间的微观结构演变及其对11Cr-3W-3Co耐热钢蠕变行为的影响。在650°C下短期热时效（>750小时）后，在与PAG边界、马氏体板条边界和M23C6碳化物相邻的区域发现了Laves相，并且随着时效时间增加逐渐吞并相邻的M23C6碳化物。较高的Si和P含量是长期时效过程中Laves相成核的良好促进剂。此外，研究了Laves相、M23C6和MX的粗化行为。随着时效时间增加，上述示例中析出相之间的粗化行为表现出显著的变化，本文对此进行了详细讨论，并且还详细分析了亚晶粒尺寸的演变。亚晶粒尺寸的增加速率总体上与M23C6碳化物尺寸的增加速率一致。不同时效时间下的位错密度演变显示出明显差异，并且在长期时效后，位错密度的降低速率受到析出相的显著影响。随着时效时间增加，材料的蠕变性能显著下降，这与长期时效过程中M23C6碳化物和亚晶粒等析出相的粗化密切相关。
