The Influence of Grain Boundaries on Crystal Structure and Tensile Mechanical Properties of Al0.1CoCrFeNi High-Entropy Alloys Studied by Molecular Dynamics Method

The mechanical properties of high-entropy alloys are superior to those of traditional alloys. However, the key problem of finding a strengthening mechanism is still challenging. In this work, the molecular dynamics method is used to calculate the tensile properties of face-centered cubic Al0.1CoCrFeNi high-entropy alloys containing Σ3 grain boundaries and without grain boundary. The atomic model was established by the melting rapid cooling method, then stretched by the static drawing method. The common neighbor analysis and dislocation extraction algorithm are used to analyze the crystal evolution mechanism of Σ3 grain boundaries to improve the material properties of high-entropy alloys during the tensile test. The results show that compared with the mechanical properties Al0.1CoCrFeNi high-entropy alloys without grain boundary, the yield strength and Young’s modulus of a high-entropy alloy containing Σ3 grain boundary are obviously larger than that of high-entropy alloys without grain boundary. Dislocation type includes mainly 1/6<112> Shockley partial dislocations, a small account of 1/6<110> Stair-rod, 1/2<110>perfect dislocation, and 1/3<111> Hirth dislocations. The mechanical properties of high-entropy alloys are improved by dislocation entanglement and accumulation near the grain boundary.

Molecular dynamics study of the influence of supercooling temperature and orientation of the crystallization front on its velocity in silver

The molecular dynamics method was used to study the influence of the supercooling temperature and the orientation of the crystallization front relative to the growing crystal on the front velocity in silver. According to the data obtained, the crystallization velocity with an increase in the supercooling temperature does not increase monotonically, but has a maximum at about 0.7-Tm (Tm is melting temperature), after which it gradually decreases, which is explained by a decrease in the diffusion mobility of atoms in the amorphous phase. Crystallization proceeds faster with the orientation of the front plane (100), slower - with the (110) and (111) orientations.

Interfacial Interactions of Phosphatidylglycerol with Oligonucleotide DNA Revealed by Molecular Dynamics Method

An interaction of DNA with lipids is of great interest because of their functions. As fatty acids and lipids can specifically bind to nucleic acids forming a code sequence of the genomic DNA, it is important to study the interaction of the oligonucleotide DNA (dA)20•(dT)20 with phosphatidylglycerol by the molecular dynamics method. Molecular docking has shown that these components form a stable complex with 5.8 kcal/mole binding energy, wherein the lipid is located in the DNA minor groove. This configuration marks 354 atom groups separated by a distance less than 3.4 Ǻ. The van der Waals and hydrophobic interactions play the leading part in the DNA-phospholipid complex stabilization along with hydrogen bonds.