Molecular Dynamics Simulation of Tensile Mechanical Properties of Ni/Ni3Al

Abstract:

The tensile mechanical properties of Ni/Ni₃Al are simulated by molecular dynamics. First, the effect of the content of γ′ strengthening phase on the tensile mechanical properties of Ni/Ni₃Al is studied at room temperature and constant strain rate. The microstructure evolution of Ni/Ni₃Al under the content of γ′ strengthening phase with three typical characteristics is especially investigated. Compared with single crystal Ni, it is found that the γ′ 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, temperature effect of the tensile mechanical properties of Ni/Ni₃Al is studied, and it is found that the tensile strength of Ni/Ni₃Al-10 vol%Ni₃Al decreased with increasing temperature. This is because as the temperature increases, the internal kinetic energy of the atom increases, resulting in the more intense thermal motion of the atoms, and the weaker the bonding force between the atoms. The atoms leaving the equilibrium position have no time to return to the equilibrium position, and the FCC structure is transformed 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 is studied. The results show that the tensile strength is not sensitive to low strain rate, but sensitive to high strain rate.