Ordering and phase separation in Ni–Cr–Al: Monte Carlo simulations vs three-dimensional atom probe

Cristelle Pareige (1) , F. Soisson (2) , G. Martin , Didier Blavette (1)

1 GPM - Groupe de physique des matériaux
2 SRMP - Service de recherches de métallurgie physique

Ordering and phase separation in Ni-Cr-Al alloys were studied using Monte Carlo (MC) simulation and three-dimensional atom probe. Excellent agreement was found. Simulation showed that. (i) in the gamma' phase, Cr substitutes for both Al and Ni sublattices; (ii) in the gamma phase, a "Ni3Cr"-type and an Ll(2)-type short range order (SRO) develop, and transient Al-rich Ll(2) ordered zones exist. In low supersaturated alloy a nucleation and growth mechanism was observed. Simulations indicated that phase transformation occurred in three stages: I-SRO develops: a "Ni3Cr"-type and an Ll(2)-type; II-formation of Al enriched and ordered zones; III-growth and coarsening of gamma' particles. Simulations of high supersaturated alloys showed that a high density of Ll(2) ordered zones nucleates before unmixing. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights received.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Cristelle Pareige, F. Soisson, G. Martin, Didier Blavette. Ordering and phase separation in Ni–Cr–Al: Monte Carlo simulations vs three-dimensional atom probe. Acta Materialia, 1999, 47 (6), pp.1889-1899. ⟨10.1016/S1359-6454(99)00054-3⟩. ⟨hal-02107703⟩