Phase evolution in two-phase alloys during severe plastic deformation

N Pant and N Verma and Y Ashkenazy and P Bellon and RS Averback, ACTA MATERIALIA, 210, 116826 (2021).

DOI: 10.1016/j.actamat.2021.116826

Phase evolution in FCC metals with strongly interacting alloy components during severe plastic deforma-tion is investigated using molecular dynamics simulations. Specifically, we study the alloy microstructure in steady state, nucleation and growth of precipitates in supersaturated alloys, and the dissolution of pre-cipitates in undersaturated alloys. The results are compared to a modified effective temperature model, providing a physical understanding for the atomic processes underlying the model and a perspective on its strengths and weaknesses. Key observations in this work are nucleation and growth of precipitates during SPD at a temperature of 100 K; Gibbs-Thomson-like behavior relating steady-state solubility to precipitate size under sustained shearing; a direct relationship between the effective temperature and the shear modulus; and the importance of cluster agglomeration during precipitate growth. The study also reveals that the mechanism of forced chemical mixing depends on precipitate size, adding compli-cations for effective temperature models describing inhomogeneous systems. The simulations are shown to provide good semi-quantitative agreement with experimental findings reported in the literature. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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