Effect of alloying with titanium on the microstructure of an oxide dispersion strengthened 13.5% Cr steel

Abstract

Microstructure and phase composition of a high chromium oxide dispersion strengthened (ODS) steel Fe-13.5% Cr-2% W-0.3% Y 2 O 3 without a titanium additive, as well as alloyed with 0.2, 0.3, and 0.4 wt % Ti, has been studied using transmission electron microscopy. A comparison of the nanoscale state of the steels under investigation with that of an ODS Eurofer steel alloyed with 0.2 wt % V has been carried out. In all of the states found, a high number density of nanosized oxide inclusions has been observed. Upon an increase of the titanium concentration in the steel Fe-13.5% Cr-2% W-0.3% Y 2 O 3 to 0.3 wt %, the average size of the particles decreases, while their number density grows. In this steel, single nanosized (0.1-0.7 µm) grains or their agglomerates have been found, as well as coarse (6-8 µm) grains.

Research Progress of ODS FeCrAl Alloys–A Review of Composition Design

“…For a suitable amount of addition, research showed that excessive Ti leads to coarsening of oxide particles in the alloy, as shown in Figure 6 of Ref. [ 124 ], or produces potential embrittlement due to large TiO 2 particles [ 125 ], which will damage the mechanical properties. The ternary Y–Ti–O composition diagram [ 126 ] well explains the influence of the Ti content on the type of Y–Ti–O phase.…”

Chemical Redistribution and Microstructural Evolution of ODS Fe-Cr Powders During Mechanical Alloying

“…Oxide dispersion strengthened (ODS) steels are promising structural materials for Generation IV nuclear fission systems and fusion reactors due to their excellent resistance at high mechanical stress and temperature [1][2][3][4][5][6][7]. The dispersion and high density of homogenous nanoscale oxide particles inside a ferritic matrix provide higher operating temperatures, a strengthening effect and a trap for the insoluble helium produced by transmutation reactions [8,9].…”