The objective of this work was to achieve a single crystalline (SX) clad on the tip of an SX turbine blade. It was assumed that remelting could extend the SX-height by resolidifying the misoriented volume of its clad tracks. Thus, remelting was used as a tool to ease the clad epitaxy. All tests were performed with SX Ni-based superalloys CMSX-4 or PWA 1426. To determine the remelting parameters, the following methodology was devised: An ideal energy input per unit was determined for each clad track shape by applying a variable laser power during the process while traveling steadily. The energy value was defined using a combination of cross-sectional analyses and different laser parameters, thereby reducing the number of required tests to find the effective track remelting parameters. This was then tested thoroughly on five differently shaped CMSX-4 clad tracks to evaluate its validity. Thereafter, the remelting parameters from one chosen CMSX-4 track were applied to a similarly shaped PWA 1426 track, resulting in a complete SX clad track. This SX track was used to form the SX deposition on top of the blade, which was also made of PWA 1426. The tests to evaluate the remelting methodology were carried out on (010)/[100] or (010)/[001] crystalline orientations, which are equivalent to the orientations found on a turbine blade tip.

Laser metal deposition (LMD) is increasingly becoming an interesting tool in recent years, especially as one capable of repairing complex metal parts or depositing special materials over the surfaces of high-reliability components. Regardless of the application, and when and where LMD is used, material microstructure optimization is aimed in order to achieve better component performance. The conjunction of LMD with laser remelting was already researched in order to achieve superior properties; however, the mathematical understanding of how the remelting process parameters influence the outcome regarding the amount of material affected is still blurry. Having this in mind, this work combined experimentation and measuring techniques in a design of experiments to obtain data from remelted LMD tracks, thus attempting to evaluate the relationship between remelting speed, laser power, and remolten volume. The procedure used in such design of experiments, and the mathematical correlations developed, are brought here to ease process parametrization of the laser deposition and remelting of Inconel 625. Confirming the findings in previous works, it was observed that it is possible to obtain a relation between laser power and laser remelting speed to a given amount of the remelted material, albeit improvement was possible due to changes in considerations and a broader design of experiments. By the end, with known clad dimensions and a laser remelting speed chosen, specific laser powers could be calculated for a desired amount of material to be remelt with more precision. The main source of deviation is judged to be the differences between the observed and the assumed perpendicular remelted profiles. Compensation for this deviation remains for further works. Nonetheless, an exponential mathematical correlation between the process parameters and the quantity of remelted material on a clad was found. Such correlation can be used to ease the remelting process parametrization of almost any given clad with small error, allowing then, through track laser remelting, the overall improvement of LMD deposition.

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