Study the effects of factors on the structure and phase transition of bulk Ag by molecular dynamics method

摘要

This paper studies the effect of atoms number (N) of bulk Ag: N = 2916 atoms (Ag_(2916)), 4000 atoms (Ag_(4000)), 5324 atoms (Ag_(5324)), 6912 atoms (Ag_(6912)) at temperature T = 300 K, 400 K, 500 K, 600 K, 700 K, 800 K, 900 K, 1000 K on bulk Ag_(5324) and annealing time t = 200 ps on the structure and phase transition of Ag bulk by Molecular Dynamics (MD) method with Sutton-Chen (SC) pair interaction potential, periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the total energy of the system (Etot), the size (l), the phase transition (determined by the relationship between Etot and T), and combined with the Common Neighbors Analysis (CNA) method. The obtained results show that the first peak's position (r) of the RDF has negligible change value, r = 2.78 A, which is completely consistent with the experimental results. For bulk Ag, there are always four types of structure: FCC, HCP, BCC, Amor and glass transition temperature T_g = 500 K. When decreasing the temperature, bulk Ag changes from liquid state to crystalline state, when increasing the annealing time at T_g = 500 K, bulk Ag changes from amorphous phase to crystalline phase state, leading to the increase of FCC, HCP, BCC structures and the decrease of Amor structure. The obtained results will be used as guide for future experiments.