To investigate the effect of nanoindentation velocity on dislocation nucleation, development and elastic deformation of 3C-SiC ceramic specimens, the nanoindentation loading process of 3C-SiC ceramic specimens under a diamond indenter is simulated. The molecular dynamics models of diamond indenter and 3C-SiC amorphous layer are constructed, and the nanoindentation conditions such as potential function, relaxation synthesis and time step are optimized. The dislocation analysis method and the identify diamond structure method are used to analyze the internal structure change of the specimen and the dislocation generation, change and transfer of different positions after nanoindentation simulation. It is found that with the increase of indenter velocity, the elastic threshold decreases and the plasticity increases, and tends to be stable at a certain stage. The load fluctuation tends to be flat, the total amount of dislocation generated continues to decrease, and the diffusion rate of dislocation slows down. The length of 1/2<110> and 1/6<112> type dislocation becomes shorter, indentation formation of the 'lotus' shape more regularly. The elastic-plastic threshold of 3C-SiC ceramic material also changes with the change of indenter velocity, and the dislocation formation rate and total amount also affect while show a certain regularity

Keywords: molecular dynamics nanoindentation, 3C-SiC ceramic, deformation mechanism, indenter velocity