Precipitation Behavior of M<sub>23</sub>C<sub>6</sub> and Fe<sub>2</sub>W in 9Cr3W3CoVNbBN Steel during Tempering in the Temperature Range of 500–790°C

The precipitation behavior of M23C6 and Fe2W was investigated in a boron-doped 9%Cr-3%W-3%Co steel during tempering at temperatures from 500 to 790°C. During tempering at high temperatures, M23C6 precipitation occurred earlier than Fe2W, but this precipitation sequence was reversed below 550°C. The Fe2W precipitates formed on PAGBs during tempering at the lower temperatures showed a continuous film morphology. The film-shaped Fe2W precipitates were stable after aging for at least 100 h at 650°C.