Short-range order in ab initio computer generated amorphous and liquid Cu–Zr alloys: A new approach

Review on Quantum Mechanically Guided Design of Ultra-Strong Metallic Glasses

“…Our ab initio approach starts with a cubic supercell containing in the order of 115 atoms (Hostert et al, 2011), which is in line with the typical size of a supercell for glassy structures found in literature (Hui et al, 2008b;Fang et al, 2009;Fujita et al, 2009;Hirata et al, 2011;Tian et al, 2011;Galván-Colín et al, 2015;Zhang et al, 2015;Huang et al, 2016) and represents the lower limit required for physically significant models (Holmström et al, 2010). This cell is then annealed at an extremely high temperature such as 4000 K for 400 fs (Hostert et al, 2011), then quenched to 0 K (Hostert et al, 2011;Schnabel et al, 2015) or room temperature (Zhang et al, 2015) with infinite quenching rate.…”

“…Thereby, structures consistent with physical samples can be achieved (Galván-Colín et al, 2015). The ab initio models are probed for consistency with physical samples by comparison with experimentally obtained X-ray scattering data (Ganesh and Widom, 2008;Hui et al, 2009;Hirata et al, 2011;Hostert et al, 2011;Wu et al, 2012;Galván-Colín et al, 2015;Huang et al, 2016;Yu et al, 2016), extended X-ray absorption fine structure (EXAFS) (Fujita et al, 2009;, electron nano-beam diffraction (Hirata et al, 2011), density (Hostert et al, 2011) and coordination numbers (Fang et al, 2009).…”

“…At the final temperature, the atomic structure is equilibrated (Hostert et al, 2011;Zhang et al, 2015;Yu et al, 2016). The heating -quenching -equilibration cycle is done once (Fang et al, 2009;Fujita et al, 2009;Galván-Colín et al, 2015;Zhang et al, 2015) or repeatedly until the volume is self-consistent (Hostert et al, 2011).…”

“…Alternative approaches to obtain an amorphous configuration include: stepwise cooling to simulate a cooling rate (Hui et al, 2008b;Fang et al, 2009;Fujita et al, 2009;Hirata et al, 2011;Tian et al, 2011;Durandurdu, 2012;Wu et al, 2012;Hunca et al, 2016;Yu et al, 2016); cooling a supercell from melt, equilibration below the melting point and subsequent cooling to room temperature with an imposed cooling rate (Qin et al, 2007;Jakse and Pasturel, 2008;Hui et al, 2009;Huang et al, 2016); or by conducting several tempering steps (Ganesh and Widom, 2008;Hui et al, 2008a). Thereby, structures consistent with physical samples can be achieved (Galván-Colín et al, 2015). The ab initio models are probed for consistency with physical samples by comparison with experimentally obtained X-ray scattering data (Ganesh and Widom, 2008;Hui et al, 2009;Hirata et al, 2011;Hostert et al, 2011;Wu et al, 2012;Galván-Colín et al, 2015;Huang et al, 2016;Yu et al, 2016), extended X-ray absorption fine structure (EXAFS) (Fujita et al, 2009;, electron nano-beam diffraction (Hirata et al, 2011), density (Hostert et al, 2011) and coordination numbers (Fang et al, 2009).…”

<em><span>Ab initio</span></em><span> generation of binary alloy foams: the case of amorphous Cu₆₄Zr₃₆</span>

“…First, we start from two initial cubic supercells with 108 atoms, i.e., 69 Cu atoms and 39 Zr atoms: an amorphous cubic supercell (a-Cu64Zr36), whose generation details are fully commented elsewhere [20][21][22]; and second, from an unstable crystalline configuration (c-Cu64Zr36) selected in order to foster disorder during the molecular dynamics process. The EL method is applied then to each sample using the following relation: l2 = 2 1/3 l1, where l2 is the edge of the expanded cell and l1 is the initial edge of the supercell [11]; this lowers the density from 8.06 g/cm 3 to 4.03 g/cm 3 (Fig.…”