Computer simulation of the matrix–inclusion interphase in bulk metallic glass based nanocomposites

Abstract

Atomistic models for matrix-inclusion systems are generated. Analyses of the systems show that interphase layers of finite thickness appear interlinking the surface of the nanocrystalline inclusion and the embedding amorphous matrix. In a first approximation, the interphase is characterized as an amorphous structure with a density slightly reduced compared to that of the matrix. This result holds for both monatomic hard sphere systems and a Cu(47.5)Zr(47.5)Al(5) alloy simulated by molecular dynamics (MD). The elastic shear and bulk modulus of the interphase are calculated by simulated deformation of the MD systems. Both moduli diminish with decreasing density but the shear modulus is more sensitive against density reduction by one order of magnitude. This result explains recent observations of shear band initiation at the amorphous-crystalline interface during plastic deformation.

Locally fluctuating cooling rate as possible reason for non-crystalline plasticity in metallic glasses

“…Tg and T l denote the experimental values [23] of glass and liquidus temperature, respectively. procedure described elsewhere [30]. The results are given in table 1.…”

In situ correlation between metastable phase-transformation mechanism and kinetics in a metallic glass

“…For EML, the solidification is nucleation-dominated for all phases that formed from the supercooled liquid. The solidification mechanism was nearly independent of Δ T in the range 141–251 K, where the latter corresponds to 953 K (0.83 T s ) which lies below the expected maximum in the polymorphic crystal-growth rate at ~1000 K 40 , 41 . There was a tendency for Cu 2 ZrAl to nucleate before the CuZr 2 phase at smaller Δ T , whereas they formed in parallel at larger Δ T .…”

Forced Enhanced Atomic Refinement Modeling of the Metallic Glass Cu46Zr46Al8

“…Cu-Zr BMG gained particular interest after its discovery challenged the pre-existing understanding of GFA. [8] For these reasons, Cu-Zr-Al forms one of the most highly researched materials in the BMG family with both experimental [9][10][11][12][13] and theoretical work [14][15][16] being reported. Georgarakis et al, [9] with his X-ray pair distribution function (PDF) experiments, showed that the addition of Al to Cu-Zr BMG induces changes in the atomic structure in the short and medium range order, attributed to the strong bonding preference between Zr and Al atoms.…”