Effects of the Boron Addition on the Microstructural Evolution and Mechanical Properties of a 14Cr ODS Ferritic Steel

摘要

In recent years, the increase of thermal efficiency in power plants has been the primary driving force todevelop materials with exceptional high temperature properties to be used in next-generation fusion andfission reactor applications. The boundary and sub-boundary hardening is one of the most importantstrengthening mechanism in creep of 14Cr steels. In this work, a ferritic 14Cr Oxide DispersionStrengthened (ODS) steel was mechanically alloyed with titanium, Y2O3 and boron in order to be comparedwith other two ODS steels with different compositions. Boron was added in relatively high percentages (0.1wt%) to study its effect over the grain boundaries and, to ensure its diffusion in the ferritic matrix during themilling stage. Afterwards, Spark Plasma Sintering (SPS) was employed as a consolidation technique to limitthe grain growth so that the bimodal morphology of the grains remained. Mechanical properties were testedby tensile tests and Vickers microhardness.