Laser Epitaxial Cladding of Ni-Base Single Crystal Superalloy
Microstructure and crystallographic orientation in the overlay weld metal have been investigated using Ni-base single crystal superalloy CMSX-4. Laser power, laser scanning speed and wire feeding speed were varied. The microstructure and crystal orientation were analyzed by microscopy and electron backscattered diffraction pattern. Microstructural observation revealed that the overlay weld metal grew epitaxially on the substrate and stray crystal tended to be formed at the conditions of high power and high Vf/Vw (Vf: Wire feeding speed, Vw: Laser scanning speed). In addition, solidification morphology, dendrite growth direction and single-crystallized condition were evaluated by combining solidification model to heat conduction model. These predicted results agreed qualitatively with the experimental ones. Based on the above results, the singlecrystallized cladding with ten passes could be achieved.
Changhee Lee, Jong-Bong Lee, Dong-Hwan Park and Suck-Joo Na
Y. Fujita et al., "Laser Epitaxial Cladding of Ni-Base Single Crystal Superalloy", Materials Science Forum, Vols. 580-582, pp. 67-70, 2008