The microstructural evolution and certain mechanical properties of three G115 steels, 9 Cr-(2.3, 2.6, 3.0) W-3 Co (wt%), were investigated after thermal aging at 675 °C for different times using optical microscopy, field emission transmission electron microscopy, X-ray diffraction, post-aged tensile tests and impact tests, focusing on martensitic lath, dislocations and precipitates. The results show that the coarsening rates of the lath and Laves phase particles increased with the increase in W concentration during thermal aging. The rates of the decreases in the dislocation and particle densities of the Laves phase particles increased with the increase in W concentration during thermal aging. Both the coarsening rates of the lath and precipitates (i.e., M₂₃C₆ and Laves phase particles) and reduction rate of the dislocation density are higher in the first 1000 h compared to those in the following 4000 h during the thermal aging process. As predicted using the Orowan stress formula, the 2.3W G115 steel revealed the best creep strength during service, among the three steels.

在675°C的温度下进行了不同时效的光学显微镜研究了三种G115钢（9 Cr-（2.3，2.6，3.0）W-3 Co（wt％））的组织演变和某些力学性能，并通过光学显微镜观察了场发射电子显微镜，X射线衍射，时效后的拉伸试验和冲击试验，重点放在马氏体板条，位错和沉淀物上。结果表明，在热时效过程中，随着W浓度的增加，板条和Laves相的粗化速率增加。Laves相颗粒的位错减少速率和颗粒密度随热老化过程中W浓度的增加而增加。板条和析出物的粗化率（即M ₂₃ C ₆在热老化过程中，前1000h的位错密度和降低速率的速率要比后4000h的高。如使用Orowan应力公式所预测的，2.3W G115钢在使用过程中显示出三种钢中最佳的蠕变强度。