Formation of Z-Phase Particles in a Martensitic 9% Cr Steel during Creep at 650°C and Their Influence on the Creep
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Abstract—The mechanism of the nucleation of Z-phase (CrVN) particles in a martensitic 10Kh9K3V2MFBR steel (9 wt % Cr) during creep at a temperature of 650°C is studied. The nucleation mechanism of Z-phase particles at a creep temperature of 650°C is found to be restructuring of the crystal lattice of V(C,N) carbonitrides due to the diffusion of chromium atoms. The transformation of nanosized V(C,N) carbonitrides into Z-phase particles is shown to weakly contribute to the structural degradation in the steel and not to cause its premature fracture during creep at 650°C if at least 50% V(C,N) carbonitrides of the initial volume fraction of these particles are retained (even at a large average size (≈200 nm) of Z-phase particles).
We thank the Technologies and Materials core facility of Belgorod State University for supplying their equipment for the structural investigations.
This work was supported by the Russian Foundation for Basic Research, project no. 18-38-00002 mol_a.
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