Effect of Liquid State Organization on Nanostructure and Strength of Model Multicomponent Solids

When a multicomponent liquid composed of particles with random interactions is slowly cooled below the freezing temperature, the fluid reorganizes in order to increase (decrease) the number of strong (weak) attractive interactions and solidifies into a structure composed of domains of strongly and of weakly interacting particles. Using Langevin dynamics simulations of a model system we find that the tensile strength, mode of fracture, and thermal stability of such solids differ from those of one-component solids and that these properties can be controlled by the method of preparation.

Figure 1

(a) shows potential energy per particle ${\epsilon }_p$ vs temperature of 1C (curve 1) and AID (curves 2, 3, 4) systems. When the AID system is slowly cooled to $T=0$ with $dT/dt={10}^{-5}/{\tau }_{LJ}$, it freezes into a crystal with no defects (curve 2) or with defects (curve 3). Curve 4 represents an AID system slowly cooled to $T=1$, equilibrated at $T=1$ and then cooled to $T=0$. (b) shows $⟨{\epsilon }_i^{\mathrm{eff}}⟩$ vs $T$ for curves 2, 3, and 4. Inset in (b) shows the radial distribution function of AID system at $T=5$ and 2.5. Typical snapshots corresponding to curves 2, 3, and 4 are shown in the lower panels. Particles are colored according to ${\epsilon }_i^{\mathrm{eff}}$ values.

Figure 2

Typical snapshots of fracture mode of AID and 1C system during uniaxial loading simulation done at $T=0$ (upper panels) and $T=0.5$ (lower panels). Initial spatial configuration for both systems corresponds to preparation by quench-equilibrate-quench method (case 4 in Fig 1). Particles are colored according to potential energy.

Figure 3

(a), (b), and (c) represent stress-strain curves for three different initial configurations corresponding to continuous cooling without defects, continuous cooling with defects and quench-equilibrate-quench methods of preparation represented by curves 2, 3, and 4 in Fig. 1, respectively. Uniaxial loading simulation is performed at $T=0$ and $T=0.5$. 1C system used for comparison has exactly same initial spatial configuration as quenched AID system.