Molecular Dynamics Study on Deformation Mechanism of Single-Crystal Titanium

The deformation mechanism of single-crystal titanium was investigated by molecular dynamics simulation at 500-1000 K with the strain rate of 0.0001-0.01 ps(-1), and the loading mode was tension and compression. The results were subjected to the stress-strain analysis, potential analysis, coevolutionary neighbourhood analysis and dislocation density analysis. The results show that with the increase in temperature, the yield strength decreases, and the strain value corresponding to the yield point decreases; at the same temperature, the tensile yield strength is slightly higher than the compressive yield strength; the modulus of elasticity does not change much under different loading rates, and the yield strength increases with the increase in loading rate. With the increase in temperature or loading rate, the peak potential energy of the system increases. As the strain proceeds, the hcp structure decreases, the Other structure increases, and the bcc and fcc structures appear and increase (except at the deformation temperature of 1000 K); after exceeding the yield point, the various structures gradually tend to be stable; with the increase in temperature, the transformation of crystal structure occurs earlier. The dislocation density decreases with increasing temperature, and the total dislocation density under tensile load is larger than that under compressive load; the main types of dislocations throughout the deformation process are Other dislocations, 1/3<(-)1100> dislocations and 1/3<112(-)0> dislocations.