Synthesis and Characterization of 17 Cr Ferritic ODS Steel Developed Through Vacuum Hot Pressing

In the present investigation, on 17 Cr ferritic oxide dispersion strengthened (ODS) steel composition of (430L + 0.3Y₂O₃ + 0.5ZrO₂ + 0.1Ti) wt% (alloy A) and (430L + 0.3Y₂O₃ + 0.5ZrO₂ + 0.1Ti + 4Al) wt% (alloy B) were developed through mechanical alloying (MA) using VHP (vacuum hot pressing). The mechanically alloyed powders were taken at different milling time intervals for confirming the nanocrystalline size using X-Ray Diffraction (XRD). Finally, 20 h of milled powders were consolidated through vacuum hot pressing (VHP) at 1180 °C in the pressure levels of 60 MPa, and the cooling rate of 50^°C/min. Throughout the experiments, the vacuum level was maintained by 10⁻³ Torr. Hot-pressed samples were subjected to densification studies; microstructural examination and hardness were analyzed in the current study. The nanocrystalline size of 3.6 nm (alloy A) and 6 nm (alloy B) were obtained at 20 h of milling time. The highest hot-pressed density of 7.60 g/cc (99% theoretical density) was acquired for aluminium-free ferritic ODS steel (alloy A) pressure at 60 MPa, whereas aluminium-contained alloy B lesser hot-pressed density of 7.34 g/cc was obtained. The microstructures of alloy A and alloy B containing ferrite along with complex oxides such as (Y–Zr–Ti–O) and (Y–Zr–Ti–Al–O), which is evident from TEM-EDS analysis. Alloy A has a higher hardness (870 VHN) due to the fine grains structure of material compared with alloy B (764 VHN).