Effects of crystal orientation on microstructures of molten pool during laser surface remelting

Detailed experimental researches on the effects of crystallography of matrix on the microstructure evolution of the laser molten pool during solidification were carried out with a DD2 single crystal specimen by using a 5 kW CO₂ laser. The experimental results show that the crystallographic direction of matrix can obviously influence the direction of dendrite growth and crystallographic effects are greater than that of heat flux during dendrite growth. On the same crystal face, the microstructures in the molten pool are very different when laser beam scanning along different crystal orientation.