Molecular dynamics study on the nanoscale repeated friction and wear mechanisms of TiC/Ni composites

In this study, the molecular dynamics method was used to simulate the process of repeated friction of TiC/Ni composites under a hard diamond grinding ball and the mechanical properties of abrasion depth and morphology, wear rate, atomic displacement, internal defect evolution, and temperature, were systematically investigated during multiple friction processes. It was found that when the action of the grinding ball on the workpiece is transmitted to the TiC phase, extreme value of friction force appears, the depth of the abrasion marks is shallow, the number of atoms in the workpiece that undergo large displacements is low, the atoms exhibit a tendency to bypass the TiC phase for displacement, and the TiC is subjected to external action energy, which leads to an increase in temperature and discontinuity in the workpiece temperature distribution. During repeated friction processes, the friction force reaches a maximum, the friction coefficient fluctuates drastically, the increment in the abrasion depth decreases, the large structural defects generated by initial friction events are decomposed into small structural defects or stable laminar dislocation tetrahedral structures leading to the formation of dislocation entanglement which improves the overall wear resistance of the workpiece, the temperature of the TiC increases rapidly, and the temperature difference compared to the substrate gradually increases.