Role of Chromium Content on the Microstructure and Mechanical Properties of Lanthana Based Ferritic ODS Steels

In the current study, lanthana (La 2 O 3 ) based oxide dispersion strengthened (ODS) ferritic steels (Fe– x Cr–1Ti–1W–0.5L 2 O 3 , x = 14, 18, 22, and 26, in wt%) have been fabricated by mechanical alloying and spark plasma sintering. The role of chromium (Cr) content and maximum sintering temperature (1050 and 1100 °C) on the density, microstructure and mechanical properties of the ODS steels have been studied. TEM analysis of the alloy revealed the presence of nano-sized (2–8 nm) complex oxide particles, i.e., La–Ti–Cr–O. Mechanical properties were estimated in terms of micro-hardness, nano-hardness, Young’s modulus and compressive strength. The highest micro-hardness (988 ± 11.3 HV) and compressive strength (2322 ± 49 MPa) were exhibited by the alloy having 26 wt% Cr, sintered at 1100 °C. The contribution of dispersion strengthening towards the strength was calculated to be the highest (~ 72%). Overall, increasing the Cr content improved both the room temperature compressive strength as well as the compressive fracture strain. Graphical Abstract