Abstract:
Fe-15Cr-4.5Al-2W-0.3Y-0.3Ti-0.3Zr supersaturated solid solution alloy powder was directly prepared by metal rapid cooling gas atomization method. The powder was treated by a short time (8 h) ball milling and then was placed in an iron envelope. The oxides dispersion strengthened (ODS) steel was directly formed by rolling. The microstructure characteristics and the tensile properties at different temperatures (room temperature and 400, 600, 700 ℃) of the rolled ODS steel were studied. The results show that ODS steel could be formed by rolling, and the relative density of the rolled ODS steel was 96%, which was slightly higher than that of hot isostatic pressed ODS steel with similar composition. The average grain size of the rolled ODS steel was 0.91 μm, which was smaller than that of hot isostatic pressed ODS steel with similar composition, and no significant texture feature was found. Y
4Zr
3O
12, YAlO
3 and Y
2TiO
5 nano-precipitates were observed in microstructure and the distribution density peak value of these precipitates reached 2.07×10
21 m
−3. The tensile strength of the rolled ODS steel decreased with the increase of test temperature. Comparing with that of ODS steel with similar composition formed by hot isostatic pressing, the tensile strength of the rolled ODS steel was higher below 600 ℃, was similar at 600 ℃, and was slightly lower above 600 ℃. With the increase of test temperature, the fracture mechanism of rolled ODS steel changed from brittle fracture to ductile fracture, and finally to brittle fracture again.