Eventos Anais de eventos
COBEF 2023
12th Brazilian Congress on Manufacturing Engineering
Metal Matrix Composite Coatings (Ni-Alloy:NbC) by Laser Cladding on GGG40 Substrate: Qualification Step throughout Single-Beads
Submission Author:
Lubar Eduardo Hortmann Santos Rivero , PR
Co-Authors:
Lubar Eduardo Hortmann Santos Rivero, Jeferson Trevizan Pacheco, Moises Teixeira, Adriano Scheid
Presenter: Lubar Eduardo Hortmann Santos Rivero
doi://10.26678/ABCM.COBEF2023.COF23-0390
Abstract
It is well-known that coatings have been considered in many industrial sectors, for instance, aerospace, marine, and automotive, as a way to improve the components' performance. Among a large variety of coatings processing techniques, laser cladding has shown noticeable technological advances in recent decades. Facing the opportunity to have powder-fed systems, a machine equipped with two independent powder delivery units opens a path for research of functional multi-materials, i.e., either combining different alloys by mixing them during the process or even mixing an alloy and hard particles of reinforcement to form a metal matrix composite coating with the desired microstructure and properties. The latter shows particular interest in component design to improve wear and corrosion resistance or even repairing a worn-down surface. The approach is promising and aligned with the best practices of sustainability, since a considerable part of the world’s total energy consumption is due to tribological contacts, to overcome friction, and remanufacturing worn parts and spare equipment due to wear-related failures. This work aims to assess the effect of laser power and NbC reinforcement feeding rate on the single-bead composite coatings features by laser cladding process. As the step of cladding qualification, the present investigation is a key point to further development of mechanical parts protected with multi-layered coating areas. Thus, composite coatings were processed with 1.5-, and 3.0-kW and feeding rates of 25, and 50 wt% of NbC to the Hastelloy C276 alloy on GGG40 ductile iron substrate. Characterizations involving bead geometry, dilution, microstructure, and hardness were performed. Results showed larger bead width and lower wettability angle for 3.0 kW. The former is associated with the higher burn-in-shape, as expected for gaussian energy distribution laser beams, and the latter is mainly due to the higher heat-input. Dilution from 4 to 11% and 37 to 41% was measured for 1.5 and 3.0 kW, respectively. The microstructure is comprised of Ni-FCC dendrites and interdendritic carbides for non-reinforced C276 alloy. Otherwise, composite coatings showed a more complex microstructure, comprising unmelted particles of NbC, primary petaloid NbC, Ni-FCC dendrites, and interdendritic secondary carbides. Hastelloy C276 showed hardness from 309 to 350 HV² whilst it ranged from 418 to 549 HV² for composite coatings. Regardless of the laser power, the increase in the NbC feeding rate induced harder composite coatings as a consequence of the higher carbide volume fraction.
Keywords
Laser Claddind, Powder-Fed Systems, Composite Coatings, Hastelloy C276, NbC Reinforcement, Dilution, Microstructure, hardness, Cladding Qualification
