Scalable parallel Monte Carlo algorithm for atomistic simulations of precipitation in alloys

Abstract

We present an extension of the semi-grandcanonical (SGC) ensemble that we refer to as the varianceconstrained semi-grandcanonical (VC-SGC) ensemble. It allows for transmutation Monte Carlo simulations of multicomponent systems in multiphase regions of the phase diagram and lends itself to scalable simulations on massively parallel platforms. By combining transmutation moves with molecular dynamics steps structural relaxations and thermal vibrations in realistic alloys can be taken into account. In this way, we construct a robust and efficient simulation technique that is ideally suited for large-scale simulations of precipitation in multicomponent systems in the presence of structural disorder. To illustrate the algorithm introduced in this work, we study the precipitation of Cu in nanocrystalline Fe.

Effect of grain boundary character on segregation-induced structural transitions

“…The chemical potential difference is given an initial guess and then adjusted during the simulation to achieve the required global composition [44]. Fig.…”

“…A Nose-Hoover thermo/barostat was then used to further relax the sample for 200 ps under zero pressure at different temperatures (600-1200 K in increments of 50 K). Thereafter, doping with Zr solutes was simulated using a Monte Carlo method in a variance-constrained semigrand canonical ensemble [44] after every 100 molecular dynamics steps, with the target global composition of Zr fixed to different values that increase in small increments. It should be noted that in classical semi-grand canonical ensemble Monte Carlo simulations, the global composition is adjusted by changing the chemical potential difference [32].…”

Multiscale modeling of sensory properties of Co–Ni–Al shape memory particles embedded in an Al metal matrix

“…To improve computational efficiency for the simulated large systems size, a parallel version of the described MC algorithm was implemented following the method of checkerboard subdomain spatial decomposition proposed in [12] and analyzed in more detail in [13].…”

A compound unit method for incorporating ordered compounds into lattice models of alloys

“…Lattice models provide a convenient framework for studying the evolution and stability of alloy microstructures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. These models typically focus on the mesoscale behavior of the system, describing the state of the alloy on a fixed lattice, with an interatomic potential that expresses the relative preference for different arrangements of species on the lattice.…”