Molecular Dynamics Simulation of Dislocation and Phase Transition for Ni-Based Superalloys with Twist Grain Boundary

Molecular dynamics (MD) simulation was carried out to study the dislocation and phase transition of gamma/gamma' phase interface for Ni-based superalloys with twist grain boundary (GB) under uniaxial tension. The simulation results showed that the density of the dislocation networks at the interface increased with increasing twist angle. Linear and square types of dislocations were observed at different twist GB. It has been found that the dislocation networks of the (001) phase interface showed different degrees and patterns of damage under uniaxial tension. Slip systems of Ni-based superalloys were {1 (1) over bar1} [011] and {(1) over bar 11} [0 (1) over bar1]. Moreover, the phase structures have been demonstrated by radial distribution function (RDF) analyses. The fcc-to-hcp phase transition was observed during the uniaxial tensile process. The result of the present work implied that the fcc-to-hcp phase transition had a great influence on the mechanical properties of Ni/Ni3Al twist GBs.