Microstructure and mechanical properties of austenitic ODS steel processed using Ni–20Cr

Austenitic oxide dispersion strengthened (AODS) steel of composition Fe–22Ni–18Cr–1.5W–0.22Ti–0.35Y2O3(wt%) was fabricated using Ni–20Cr (instead of commonly used Ni) in second–stage ball milling. Mechanical alloying process for producing AODS powder was studied by measuring the yield and average size of milled powder. After 5 h of second–stage milling, the yield/s of milled powder was found to be 75% with Ni–20Cr and 42% with Ni. AODS powder was subsequently consolidated using hot extrusion and solution annealed. The consolidated samples exhibited austenitic grain size of 0.43 ± 0.19 µm along with Y2Ti2O7dispersoids of size < 20 nm. Yield strength and elongation was measured as 830 MPa and 27%, respectively at room temperature, which are comparable to reported values. Thus, this study describes an alternative route to produce AODS steel with improved milled powder yield using Ni–20Cr, while still retaining higher strength levels associated with AODS steel.Graphical abstract