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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on MgAl2 by Materials Project

MgAl2 is Cuprite structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Mg is bonded to six equivalent Al atoms to form a mixture of distorted edge and corner-sharing MgAl6 octahedra. The corner-sharing octahedral tilt angles are 63°. There are two shorter (2.64 Å) and four longer (2.85 Å) Mg–Al bond lengths. Al is bonded in a 4-coordinate geometry to three equivalent Mg and one Al atom. The Al–Al bond length is 2.58 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl by Materials Project

MgAl is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mg is bonded to four equivalent Al atoms to form corner-sharing MgAl4 tetrahedra. All Mg–Al bond lengths are 2.79 Å. Al is bonded to four equivalent Mg atoms to form corner-sharing AlMg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Al by Materials Project

AlMg3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded to eight equivalent Mg and four equivalent Al atoms to form MgMg8Al4 cuboctahedra that share corners with four equivalent MgMg8Al4 cuboctahedra, corners with eight equivalent AlMg12 cuboctahedra, edges with twenty-four MgMg8Al4 cuboctahedra, faces with six equivalent AlMg12 cuboctahedra, and faces with twelve MgMg8Al4 cuboctahedra. All Mg–Mg bond lengths are 3.10 Å. All Mg–Al bond lengths are 3.10 Å. In the second Mg site, Mg is bonded to eight Mg and four equivalent Al atoms to form MgMg8Al4 cuboctahedra that share corners with twelve equivalent MgMg8Al4 cuboctahedra, edges with eight equivalent AlMg12 cuboctahedra, edges with sixteen MgMg8Al4 cuboctahedra, faces with four equivalent AlMg12 cuboctahedra, and faces with fourteen MgMg8Al4 cuboctahedra. All Mg–Mg bond lengths are 3.10 Å. All Mg–Al bond lengths are 3.10 Å. Al is bonded to twelve Mg atoms to form AlMg12 cuboctahedra that share corners with four equivalent AlMg12 cuboctahedra, corners with eight equivalent MgMg8Al4 cuboctahedra, edges with eight equivalent AlMg12 cuboctahedra, edges with sixteen equivalent MgMg8Al4 cuboctahedra, faces with four equivalent AlMg12 cuboctahedra, and faces with fourteen MgMg8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Al by Materials Project

AlMg3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a body-centered cubic geometry to eight equivalent Mg atoms. All Mg–Mg bond lengths are 3.00 Å. In the second Mg site, Mg is bonded in a distorted body-centered cubic geometry to four equivalent Mg and four equivalent Al atoms. All Mg–Al bond lengths are 3.00 Å. Al is bonded in a body-centered cubic geometry to eight equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Al by Materials Project

AlMg3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Mg is bonded to eight equivalent Mg and four equivalent Al atoms to form MgMg8Al4 cuboctahedra that share corners with four equivalent AlMg12 cuboctahedra, corners with fourteen equivalent MgMg8Al4 cuboctahedra, edges with six equivalent AlMg12 cuboctahedra, edges with twelve equivalent MgMg8Al4 cuboctahedra, faces with four equivalent AlMg12 cuboctahedra, and faces with sixteen equivalent MgMg8Al4 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.04–3.12 Å. There are two shorter (3.08 Å) and two longer (3.09 Å) Mg–Al bond lengths. Al is bonded to twelve equivalent Mg atoms to form AlMg12 cuboctahedra that share corners with six equivalent AlMg12 cuboctahedra, corners with twelve equivalent MgMg8Al4 cuboctahedra, edges with eighteen equivalent MgMg8Al4 cuboctahedra, faces with eight equivalent AlMg12 cuboctahedra, and faces with twelve equivalent MgMg8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl by Materials Project

MgAl is beta-prime cadmium gold structured and crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Mg is bonded to four equivalent Mg and eight equivalent Al atoms to form a mixture of distorted corner, edge, and face-sharing MgMg4Al8 cuboctahedra. There are two shorter (3.02 Å) and two longer (3.13 Å) Mg–Mg bond lengths. There are a spread of Mg–Al bond distances ranging from 2.94–3.09 Å. Al is bonded in a 12-coordinate geometry to eight equivalent Mg and two equivalent Al atoms. Both Al–Al bond lengths are 2.92 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Crystal Structure Prediction of Binary Alloys via Deep Potential

Predicting crystal structure has been a challenging problem in physics and materials science for a long time. A reliable energy calculation engine combined with an efficient global search algorithm, such as particle swarm optimization algorithm or genetic algorithm, is needed to conduct crystal structure prediction. In recent years, machine learning-based interatomic potential energy surface models have been proposed, potentially allowing us to perform crystal structure prediction for systems with the accuracy of density functional theory (DFT) and the speed of empirical force fields. In this paper, we employ a previously developed Deep Potential model to predict the intermetallic compound of the aluminum–magnesium system, and find six meta-stable phases with negative or nearly zero formation energy. In particular, Mg 12 Al 8 shows excellent ductility and Mg 5 Al 27 has a high Young's modulus. Based on our benchmark results, we propose a relatively robust structure screening criterion that selects potentially stable structures from the Deep Potential-based convex hull and performs DFT refinement. By using this criterion, the computational cost needed to construct the convex hull with ab initio accuracy can be dramatically reduced.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗