Ab initio simulations of clustering and precipitation in Al-Mg-Si alloys
Journal article, 2007

A class of proposed coherent precipitate structures (Guinier-Preston zones) in the Al-Mg-Si alloy are investigated using first-prin- ciples density functional theory methods. The cluster expansion method is used to extract effective interaction parameters, providing the means for large scale energy calculations of alloy structures. The Mg1Si1 L1(0) structure and structures related to the Mg5Si6 beta '' phase are studied in more detail, and e.g., precipitate/matrix interface energies are presented. Using direct first-principles calculations we show that the former phase is dynamically unstable and thus must be stabilized by the surrounding Al matrix. Monte Carlo simulations and free-energy techniques are used to study the Al rich side of the phase diagram with the current CE parameters, and kinetic Monte Carlo simulations are used to study clustering in the disordered phase. The implications of our findings are discussed in the framework of classical nucleation theories, and we outline possible nucleation mechanisms. (C) 2007 Elsevier B.V. All rights reserved.

PSEUDOPOTENTIALS

1ST-PRINCIPLES

clustering

MODEL

aluminium alloys

TRANSITION

MOLECULAR-DYNAMICS

ternary alloys

first-principles

PHASE-DIAGRAM

ZONES

cluster expansion

SYSTEMS

Author

N. Sandberg

Norwegian University of Science and Technology (NTNU)

Mattias Slabanja

Chalmers, Applied Physics, Materials and Surface Theory

R. Holmestad

Norwegian University of Science and Technology (NTNU)

Computational Materials Science

0927-0256 (ISSN)

Vol. 40 3 309-318

Subject Categories

Other Engineering and Technologies

DOI

10.1016/j.commatsci.2007.01.001

More information

Latest update

4/20/2018