On Laves phase in a 9Cr3W3CoB martensitic heat resistant steel when aged at high temperatures

9Cr3W3CoB steels are developed to serve at the temperature range of 620–650 °C, and have been recognized as the most promising martensitic heat-resistant steels for supercritical power plants. Due to the high W and Co contents, the Fe2W Laves phase in such 9Cr3 W3CoB steel possesses some specialties in thermodynamics. In the present research, it was found that even when aged at 800 °C in the 9Cr3W3CoB steel, instead of dissolving, Laves phase...