The effects of Ti and Ta addition on microstructure stability and tensile properties of a reduced activation ferritic/martensitic (RAFM) steel have been investigated. Ti addition of 0.06 wt% to conventional RAFM reference base steel (Fe-9.3Cr-0.93W-0.22V-0.094Ta-0.1C) was intended to promote the precipitation of nano-sized (Ti,W) carbides with a high resistance to coarsening. In addition, the Ti addition was substituted for 0.094 wt% Ta. The Ti-added RAFM steel (Ti-RAFM) exhibited a higher yield strength (ΔYS = 32 MPa) at 600 °C than the reference base steel due to additional precipitation hardening by (Ti,W)-rich MX with an average size of 6.1 nm and the area fraction of 2.39%. However, after thermal exposure at 600 °C for 1000 h, this Ti-RAFM was more susceptible to degradation than the reference base steel; the block width increased by 77.6% in Ti-RAFM after thermal exposure while the reference base steel showed only 9.1% increase. In order to suppress diffusion rate during thermal exposure, the large-sized Ta element with low activation was added to Ti-RAFM. The Ta-added Ti-RAFM steel exhibited good properties with outstanding microstructure stability. Quantitative comparison in microstructures was discussed with a consideration of Ti and Ta addition.

研究了Ti和Ta的添加对还原活化铁素体/马氏体（RAFM）钢的组织稳定性和拉伸性能的影响。向常规RAFM参考基础钢（Fe-9.3Cr-0.93W-0.22V-0.094Ta-0.1C）中添加0.06 wt％的Ti旨在促进具有高电阻的纳米尺寸（Ti，W）碳化物的析出变粗。另外，Ti的添加代替了0.094重量％的Ta。钛添加的RAFM钢（Ti-RAFM）表现出更高的屈服强度（Δ在600°C时，YS = 32 MPa），这是由于采用富（Ti，W）的MX进行了额外的沉淀硬化，平均尺寸为6.1 nm，面积分数为2.39％。但是，在600°C的温度下暴露1000 h后，这种Ti-RAFM比参考基础钢更容易降解。热暴露后，Ti-RAFM的块宽增加了77.6％，而参考基础钢仅增加了9.1％。为了抑制热暴露期间的扩散速率，将具有低活化性的大尺寸的Ta元素添加到Ti-RAFM中。掺钽的Ti-RAFM钢表现出良好的性能，并具有出色的显微组织稳定性。考虑了添加钛和钽，讨论了微观结构中的定量比较。