Coherent precipitation and stability of cuboidal B2 nanoparticles in a ferritic Fe–Cr–Ni–Al superalloy

Abstract

The present work developed a new Fe-based superalloy of Fe–10.9Cr–13.9Ni–6.4Al–2.2Mo–0.5W–0.04Zr–0.005B (weight percent, wt. %) with cuboidal B2 nanoparticles coherently precipitated into the body-centred-cubic (BCC) matrix. This alloy possesses excellent microstructural stability at 973 K with a slow particle coarsening rate and the B2 nanoprecipitates still keep cuboidal after 1000 h-aging, which is ascribed to the moderate lattice misfit (ϵ = 0.24–0.67%) between BCC and B2 phases. Also, the current alloy exhibits a prominent mechanical property with a high yield strength of σYS = 238–258 MPa at 973 K.

Keywords

• fe-based superalloy
• coherent precipitation
• lattice misfit
• particle coarsening
• mechanical properties