Research on the Effect Mechanism of Re on Interface Dislocation Networks of Ni-Based Single Crystal Alloys.

ABSTRACT

The effect of interface dislocation networks on the mechanical properties of new Ni-based single crystal alloys containing Rhenium (Re) is very large. Because the interface dislocations are microscopic in the nano-scale range, this has not been investigated, and it is very difficult to prepare new Ni-based single crystal alloys containing Re. Therefore, six kinds of new Ni-based single crystal alloys containing Re were prepared, and the hardness tests and nonlinear ultrasonic lamb wave tests were performed on the samples. It was found that the density of interface dislocation networks increases with the increase in the content of Re, which improves the blocking ability of matrix phase dislocation cutting into precipitated phase and enhances the inhibition of dislocation movement. The nonlinear ultrasonic lamb wave tests showed that the materials exhibit better mechanical properties when the density of the interface dislocation networks increases. Meanwhile, a new molecular dynamics model which is closer to the real state of an Ni-based single crystal alloy was constructed to reveal the evolution mechanism of interface dislocation networks. The results showed that the potential energy of Re atoms at the interface is the lowest, which affects the reduction of the potential energy of other atoms at the interface, and thus the stability of the model is improved. In addition, according to the change in the total length of dislocation loops in the model system, with the increase in the content of Re atoms, the inhibition of dislocation movement by dislocation networks at the interface is strengthened.