The Effects of Grain Boundary Misorientation on the Mechanical Properties and Mechanism of Plastic Deformation of Ni/Ni3Al: A Molecular Dynamics Study

Abstract

The effects of grain boundary misorientation angle (θ) on mechanical properties and the mechanism of plastic deformation of the Ni/Ni3Al interface under tensile loading were investigated using molecular dynamics simulations. The results show that the space lattice arrangement at the interface is dependent on grain boundary misorientations, while the interfacial energy is dependent on the arrangement. The interfacial energy varies in a W pattern as the grain boundary misorientation increases from 0° to 90°. Specifically, the interfacial energy first decreases and then increases in both segments of 0–60° and 60–90°. The yield strength, elastic modulus, and mean flow stress decrease as the interfacial energy increases. The mechanism of plastic deformation varies as the grain boundary misorientation angle (θ) increases from 0° to 90°. When θ = 0°, the microscopic plastic deformation mechanisms of the Ni and Ni3Al layers are both dominated by stacking faults induced by Shockley dislocations. When θ = 30°, 60°, and 80°, the mechanisms of plastic deformation of the Ni and Ni3Al layers are the decomposition of stacking faults into twin grain boundaries caused by extended dislocations and the proliferation of stacking faults, respectively. When θ = 90°, the mechanisms of plastic deformation of both the Ni and Ni3Al layers are dominated by twinning area growth resulting from extended dislocations.

A critical investigation of the anisotropic behavior in the WAAM-fabricated structure

“…The misorientation angle is defined as the difference between the crystallographic orientation of a single grain and its neighbors, which directly affects the grain structure, interface energy and mechanical properties of the grain boundary. The study showed that the mechanical properties of the grain boundary decrease with an increase in the angle of misorientation (Ding et al , 2020). The higher and lower rotation angles of the grain boundaries present in the different zones of the printed wall are displayed in Figure 5.…”

Misorientation Angle Study on Cleavage Fracture Propagation Surfaces of a Grade a Ship Steel, through Charpy and Four-Point Double-Notch Bend Tests

“…The misorientation angle between adjacent grains of steels, has become one of the major concerns for the study of some mechanical and toughness properties of irons [1][2][3][4][5], carbon steel [3,6], stainless steel [7][8], other types of steels [8][9][10] and different alloys [11][12]. The misorientation angle play a big role for the propagation of cleavage fracture in steels and on the fracture surface appearance.…”