Molecular Dynamics Simulation of Tensile Mechanical Properties of Ni/Ni3Al

X Zhu and WG Jiang and YC Li and H Lv, RARE METAL MATERIALS AND ENGINEERING, 50, 1254-1262 (2021).

The tensile mechanical properties of Ni/Ni3Al were simulated by molecular dynamics. First, the effect of the content of gamma' strengthening phase on the tensile mechanical properties of Ni/Ni3Al was studied at room temperature and constant strain rate. The microstructure evolution of Ni/Ni3Al under the content of gamma' strengthening phase with three typical characteristics was especially investigated. Compared with single crystal Ni, it is found that the gamma' strengthening phase can increase the tensile strength of Ni/Ni3Al. This is because during the plastic deformation process, as the dislocations continue to multiply, the dislocation density gradually increases, resulting in dislocation plugging, which increases the resistance to dislocation movement, thereby increasing the tensile strength. Secondly, the effect of temperature on the tensile mechanical properties of Ni/Ni3Al was studied, and it is found that the tensile strength of Ni/Ni3Al decreases with increasing temperature. This is because as the increasing temperature, the internal kinetic energy of the atom increases, resulting in the more intense thermal motion of the atoms, and the weaker bonding force between the atoms. The atoms leaving the equilibrium position have no time to return to the equilibrium position, and the fcc structures transform into a large number of hcp structures and other atomic arrangements, which cause lattice distortion and reduce tensile strength. Finally, the effect of strain rate on the tensile mechanical properties of Ni/Ni3Al was studied. The results show that the tensile strength is not sensitive to low strain rate, but sensitive to high strain rate.

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