To investigate the cooling mechanism and the local structural changes of excimer laserannealed silicon (Si), molecular dynamics (MD) simulations were performed. Heat flow of molten Si showed a strong dependency of the local region during a natural cooling. An amorphous-to-liquid transition near an interface in the temperature range of 1600 K ~ 1800 K was expected with the results of the local diffusion coefficients calculated by integrating the velocity autocorrelation functions. It was confirmed that the structure of the interface region affected the cooling rate of the overall system. The structural properties at the various local regions after a cooling were assessed in terms of the configurational properties including the coordination and bond-angle distributions. A spontaneous nucleation of Si near a interface was observed during a natural cooling.

Effects of precipitation on the recrystallization behavior of three Ti-added extra low carbon sheet steels were compared. The recrystallization temperature of the high Ti-containing steel is higher than that of the low Ti-containing steel. Small angle neutron scattering (SANS) measurements were performed both for cold rolled samples and for annealed samples. The size distribution and the volume fraction of the nano-sized precipitates were quantitatively determined from the corrected scattering curves using a direct model fitting with a sphere. SANS results revealed no additional carbo-nitrides precipitation during the recrystallization annealing procedure in the low Ti-containing steel. However, in the high Ti-containing steel, new TiC precipitates smaller than 10 nm formed during the recrystallization annealing process. This dynamic interaction of the precipitation of the fine TiC particles with the recovery of dislocations seems primarily responsible for the retardation of the recrystallization in the high Ti-containing extra low carbon steel.