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.