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Influences of different hydride nanoparticles on microstructure and mechanical properties of 14Cr3Al ferritic ODS steels
- Kang, Zhanbo, Shen, Hailong, Bai, Zhonglian, Zhao, Haozhi, Liu, Tong
- Powder technology 2019 v.343 pp. 137-144
- hydrides, hydrogen, microstructure, nanoparticles, powders, pressing, steel, tensile strength, zirconium
- In order to suppress the formation of large Y-Al-O particles in the Al-containing oxide dispersion strengthened (ODS) steels, spherical Zr/Hf hydride nanoparticles (NPs) of 21 ± 6 nm and 16 ± 4 nm were prepared by the hydrogen plasma metal reaction (HPMR) method and added as raw particles to produce the ODS Fe-14Cr-3Al-2 W-0.35Y2O3 steels using mechanical alloying (MA) and hot isostatic pressing (HIP). Zr/Hf hydride NPs gave rise to the formation of fine complex oxide NPs, Y4Zr3O12 of 14.2 ± 8.1 nm and Y2Hf2O7 of 9.1 ± 6.9 nm. These oxide NPs were semi-coherent with the matrix, (43¯2¯)Y4Zr3O12//(D = 2.57 × 10−17m2/s)α-Fe, and (D = 1.54 × 10−17m2/s)Y2Hf2O7//(D = 6.25 × 10−12m2/s)α-Fe. With the increasing atomic number of IVB group element (from Ti to Hf), the addition of its hydride NPs can create finer complex oxide nanoparticles in the Al-containing ODS steels and bring about higher mechanical properties. The tensile strength of the 14Cr3Al ODS steel added with 0.1 wt% Hf hydride NPs exhibited a tensile strength of 1067 MPa at 25 °C and 284 MPa at 700 °C, higher than those ODS steels added with 0.1 wt% Zr/Ti hydride NPs. Furthermore, the ODS steel added with Hf hydride showed a large uniform elongation of 11.5% at 25 °C. The addition of Hf hydride NPs is promising to develop high performance Al-containing ODS steels.