Phase transformation on new six reduced activation ferritic/martensitic steels (RAFMs) was investigated to provide the basis for the design and development of advanced steels to maintain adequate strength and creep resistance above 500 °C. The new alloys are designed to increase the amount of fine MX precipitates and reduce coarse M₂₃C₆ carbides through alloy composition refinement and the application of thermomechanical treatments. The microstructural investigations by TEM have shown M₂₃C₆, M₂X, and MX precipitation after tempering at 700 °C/2h with low dislocation recovery, while at 825 °C/2h the martensite developed to subgrain formation and growth. At this stage, only M₂₃C₆ and MX were detected. Preliminary results demonstrate that it is feasible to produce fine MX strengthened particles dispersed in the matrix with further optimization of tempering treatments.

研究了六种新的还原活化铁素体/马氏体钢（RAFM）的相变，为高级钢的设计和开发提供了基础，以在500°C以上保持足够的强度和抗蠕变性。通过合金成分的细化和热机械处理的应用，这些新合金旨在增加细小的MX析出物的数量并减少粗大的M ₂₃ C ₆碳化物。TEM的显微组织研究表明，在700°C / 2h回火后，M ₂₃ C ₆，M ₂ X和MX析出，位错回复率低，而在825°C / 2h时，马氏体发展为亚晶粒形成和生长。在这个阶段，只有M ₂₃ C检测到₆和MX。初步结果表明，通过进一步优化回火处理，可以生产出分散在基质中的细MX增强颗粒。