Influence of impurity concentration, atomic number, temperature and tempering time on microstructure and phase transformation of Ni1−xFex (x = 0.1, 0.3, 0.5) nanoparticles

Abstract

The influence of the concentration of impurity Fe in nanoparticles Ni[Formula: see text]Fe[Formula: see text] with x = 0.1, 0.3 and 0.5 at T = 300 K; 4000 atoms, 5324 atoms, 6912 atoms and 8788 atoms at T = 300 K; 6912 atoms at T = 1500 K, 1300 K, 1100 K, 900 K, 700 K, 600 K, 500 K and 300 K and tempering time t = 500 ps at 6912 atoms on microstructure, phase transition temperature of Ni[Formula: see text]Fe[Formula: see text] nanoparticles is studied by molecular dynamics method with the Sutton–Chen embedded interaction potential and liberal boundary conditions. The structural properties are analyzed through the radial distribution function, the energy, the size, the phase transition temperature (determined by the relationship between total energy and temperature) and combined with the common neighbor analysis (CNA) method. The obtained first peak positions of the radial distribution function for the lengths of atomic pair Fe–Fe, Fe–Ni and Ni–Ni are consistent with the experimental data. In Ni[Formula: see text]Fe[Formula: see text] nanoparticles always exist in three types of structures (FCC, HCP, Amor) and phase transition temperatures range from 500 K to 700 K. When the concentration of impurity Fe in Ni[Formula: see text]Fe[Formula: see text] nanoparticles increases, then nanoparticles move from crystalline to amorphous state. When Ni[Formula: see text]Fe[Formula: see text] nanoparticles are at amorphous state, then the influence of factors such as the atomic number, the temperature and the tempering time on structure and transition temperature is negligible.