Molecular dynamics (MD) was used to simulate the effect of TiC particles distribution on the tribological behavior of the reinforced composites. The mechanical properties, friction coefficient, number of wear atoms, stress and temperature, and microscopic deformation behavior of TiC/Ni composites during nano-friction were systematically investigated by MD to reveal the effect of TiC distribution on the friction removal mechanism of the material. It was found that the larger the radius of the TiC particles, or the shallower the depth of the TiC particles, the easier it was to generate stress concentrations around the TiC particles, forming a high dislocation density region and promoting the nucleation of dislocations. This leads to severe friction hardening, reducing the atomic number of abrasive chips and reducing the friction coefficient by approximately 6% for every 1 nm reduction in depth, thus improving the anti-wear capacity. However, when the radius of the TiC particles increases and the thickness from the surface deepens, the elastic recovery in material deformation is weakened. We also found that the presence of the TiC particles during the friction process changes the stress state inside the workpiece, putting the TiC particles and the surrounding nickel atoms into a high-temperature state and increasing the concentrated temperature by 30 K for every 1 nm increase in depth. Nevertheless, the workpiece atoms below the TiC particles invariably exist in a low-temperature state, which has a great insulation effect and improves the high-temperature performance of the material. The insight into the wear characteristics of TiC particles distribution provides the basis for a wide range of TiC/Ni applications.

To systematically investigate the friction and wear behavior of TiC/Ni composites under microscopic, the molecular dynamics (MD) method was used to simulate nano-friction on the TiC/Ni composite. Mechanical properties, abrasion depth, wear rates, temperature change of the material during friction, the microscopic deformation behavior, and the evolution of nickel-based titanium carbide microstructure at high-speed friction have been systematically studied. It was found that the variation of tangential and normal forces is related to the relative position of the grinding ball and the TiC phase, when the grinding ball is located above the TiC phase, large fluctuations in the frictional force occur and extreme value of normal force appears, shallow abrasion depth and low wear rate. During the friction process, there is a high-stress area between the grinding ball and the TiC phase, generating a large number of dislocations. The presence of the TiC phase hinders the development and extension of defects, resulting in a significant increase in temperature. At the same time, dislocation entanglement occurs, which improves the wear resistance of the workpiece. In addition, it was also found that the internal atomic motion guided by the carbonized phase was related to the position of the grinding ball relative to the reinforced phase, with the reinforced phase presenting a tendency to rotate in different directions when the grinding ball was in different positions relative to the reinforced phase, which in turn affected the deformation of the whole workpiece.

Duplex titanium-aluminum alloy materials have a widespread application prospect. However, understanding material wear and defect evolution under friction with different vibration amplitudes is still limited. Therefore, in this study, the anisotropy factor, atomic displacement, residual stress, temperature, dislocation density, and number of defective atoms of the forces applied to the material during friction of dual-phase titanium-aluminum alloys with different vibrational amplitudes are investigated by molecular dynamics simulations. The simulation results show that an increase in vibration amplitude leads to a decrease in the total force applied to the substrate, and the material will be stressed more uniformly. The γ-phase atoms did not pass through the two-phase interface at each vibration amplitude, and the residual stresses were also primarily located in the abrasive chips and at the two-phase interface. At the same time, many atomic structures of the γ-phase are damaged under the friction of the large vibrational amplitude, making it easier for the wear ball to accumulate the abrasive atoms on the sides. In addition, the generation of edge-type dislocations was not proportionally related to the growth of the vibration amplitude. The intertwining of numerous dislocations within the γ-phase hinders the development of dislocations and improves the matrix’s deformation resistance. Many atoms are gradually amorphized by friction at large vibrational amplitudes.