Atomic simulation of void location effect on the void growth in nickel-based single crystal

Abstract

Void growth in metallic materials are strongly affected by local microstructure. The location of defect produces a great influence on the mechanical properties of material, especially if defect occurs at the interface. Considering the complex microstructure of nickel-based single crystal, the Ni, Ni3Al and Ni/Ni3Al interface model were established to analyze the expansion dynamics of void using molecular dynamics (MD) method. The expansion behavior of void shows that a/6〈1 1 2〉 Shockley partial dislocations initially nucleates on the free surface of void during the stretching of Ni and Ni3Al model. Whereas, dislocations nucleate from the interface of Ni/Ni3Al interface model. Evolution of void suggested that the plasticity deformation is dominated by movable Shockley partial dislocations and immovable Stair-rod dislocations. Void size effect analysis revealed that the larger void radius is, the smaller yield stress and Young’s modulus are. The mechanical properties of Ni/Ni3Al interface model were controlled by the interaction between void and interface.