Turbine blade tip single crystalline clad deposition with applied remelting passes for well oriented volume extension

Abstract

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.

Effect of Laser Remelting on Tribological Performance of Ni-Cr-B-Si Coatings Deposited by Laser Metal Deposition

“…In previous works developed by the LMP-Laser group, consistent results are reported: Pôrto et al ( 2019) performed a methodology for parameterizing the remelting process of single beads deposited via LMD and observed that throughout the evaluated parameter window, especially those deposited with higher energy, resulted in complete single bead remelting. Pereira et al (2017), in the remelting evaluation applied in the misorietated volume reduction for turbine blades, they highlight similar behavior, as well as in the work, of similar objective, presented by Rottwinkel et al (2017). Cao and Gu (2015), when evaluating density ratio, microstructures, and performance of TiC / Inconel 625 nanocomposites deposited via LMD, they observed that when increasing the energy, operating temperature is high enough to increase melt pool temperature and reduce the liquid viscosity, improving wettability.…”

“…The coatings showed good surface quality concerning the layer continuity and irregularities absence (such as waviness and depressions). The remelted surface aspect was even better compared to the as-deposited surface since the first did not exhibit unmelted powder particles and showed a lower waviness level (see topic 2.1., paragraph 2) compared to the latter (Rottwinkel et al, 2017;Pôrto et al, 2019). Besides that, none of the coating samples (both as-deposited and remelted) did not show material detachments during the tribological test performed (results of which will be presented and discussed in topics 3.2. and 3.3.).…”

The Effect of Zn and Zn–WO3 Composites Nano-Coatings Deposition on Hardness and Corrosion Resistance in Steel Substrate

“…A laser cladding technique was applied to coat nickel-based composite on H13 steel, which offers enhanced wear resistance and thermal fatigue properties [ 35 ]. Although laser clad deposits produced superior properties, the small spot or concentration size of lasers hinders large widths to be deposited in a single pass [ 36 ]. Magnetron sputtered molybdenum di-sulfide titanium nitride coatings on high-speed steels produced superior surface hardness [ 37 ].…”

Effect of Pulse Frequency on the Columnar-to-Equiaxed Transition and Microstructure Formation in Quasi-Continuous-Wave Laser Powder Deposition of Single-Crystal Superalloy

“…The CW LPD process shows a potential to effectively restore worn SX components. [7][8][9][10] During the rapid solidification of the CW LPD process of SX superalloy, a high-energy laser beam continuously melts the SX base and injected metallic powders, forming a fast-moving molten pool. Fine columnar dendrites grow epitaxially with crystallographic orientation identical to the SX base.…”