Atomic-Scale Dynamic Response and Macroscopic Erosion Behavior of Titanium Nitride Coatings under Continuous Impact

In hydraulic fracturing, the solid particles carried by the fracturing fluid can severely erode the surface of the drilling equipment, leading to the failure and cracking of the material structure. However, at present, a single numerical or experimental method is unable to explain the erosion mechanism at the interface. Therefore, an innovative multiscale coupling simulation method combining macroscopic solid-liquid coupling fluid dynamics and molecular dynamics (CFD-DPM-MD) was adopted to explain the external macroscopic erosion damage from the dynamic change process of the internal microstructure of the material, and the surface damage conditions with and without coating were compared and studied. The CFD simulation indicates that the maximum erosion rate of the elbow pipe increases with the increase of the bending angle. Further MD simulation analysis shows that the TiN coating can resist nonvertical impacts through interatomic forces, while the high kinetic energy brought by vertical impacts is difficult to be counteracted, thereby exacerbating material damage. During continuous dynamic impact processes, TiN coatings exhibit excellent stress-bearing capacity by effectively suppressing the propagation of stress waves and strain fields into the substrate interior. In continuous particle impact processes, TiN coatings mainly enhance their own toughness through amorphous deformation mechanisms rather than brittle fracture, and can quickly recover after impact. This further reduces the accumulation of wear caused by superimposed impacts. This study reveals the atomic-scale dynamic response mechanism of TiN coatings and provides a theoretical basis for the antierosion mechanism of TiN coatings from a multiscale perspective.