Effect of Ti addition on hardness change during tempering in reduced activation ferritic/martensitic (RAFM) steels

The specificities of hardness change during tempering in Ti-containing reduced activation ferritic/martensitic (RAFM) steels were found while developing new RAFM steels with improved mechanical properties. Hardness decline during tempering of RAFM steel where Ti replaced Ta (Ti-RAFM) and RAFM steel with both Ta and Ti (TaTi-RAFM) was greater than that in conventional RAFM steel with Ta (Ta-RAFM). It is believed that Ti addition tend to accelerate the growth of MX precipitates and thereby accelerated diffusion of carbon from the martensite matrix, leading to a large decrease in hardness of martensite in Ti-containing RAFM steels during tempering.