Laser Cladding of Ultra-Thin Nickel-Based Superalloy Sheets

Abstract

Laser cladding is a well-established process to apply coatings on metals. However, on substrates considerably thinner than 1 mm it is only rarely described in the literature. In this work 200 µm thin sheets of nickel-based superalloy 718 are coated with a powder of a cobalt-based alloy, Co–28Cr–9W–1.5Si, by laser cladding. The process window is very narrow, therefore, a precisely controlled Yb fiber laser was used. To minimize the input of energy into the substrate, lines were deposited by setting single overlapping points. In a design of experiments (DoE) study, the process parameters of laser power, laser spot area, step size, exposure time, and solidification time were varied and optimized by examining the clad width, weld penetration, and alloying depth. The microstructure of the samples was investigated by optical microscope (OM) and scanning electron microscopy (SEM), combined with electron backscatter diffraction (EBSD) and energy dispersive X-ray spectroscopy (EDX). Similarly to laser cladding of thicker substrates, the laser power shows the highest influence on the resulting clad. With a higher laser power, the clad width and alloying depth increase, and with a larger laser spot area the weld penetration decreases. If the process parameters are controlled precisely, laser cladding of such thin sheets is manageable.

Performance Comparison of Advanced Ceramic Cladding Approaches via Solid-State and Traditional Welding Processes: A Review

“…The heat is supplied by a laser source on a highly concentrated zone where the cladding powder is kept on the substrate’s surface, as shown in Figure 5 . The high temperatures promote the melting of the mixture with the substrate, melted by thermal conduction through the pre-placed layer [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. Due to the interaction with the cold substrate, rapid solidification occurs, which improves mechanical properties.…”

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

“…Typically, laser cladding is performed on substrates with thicknesses of multiple millimeters, such as cylinders [11,12] or plates [13,14]. The application of laser cladding on thin-sheet substrates was first reported by Burmester et al [15] and has only been scarcely studied in the literature for sheets with a thickness below 10 mm [16,17], as well as below 1 mm [15,18,19]. As the use of high-power, continuous-wave (cw) lasers have yielded excess energy input and distortion, Burmester et al [15] employed a pulsed Nd:YAG-laser to limit the energy input and a chilled clamping device, which allows for cooling of the sheet during laser cladding.…”

“…With a focus on solidification and microstructural evolution, a pulsed Nd:YAG-laser was also used by Farnia et al [17] to clad pre-placed Stellite 6 powder on sheets of low-carbon steel. Laser systems operating in cw-mode were first used for cladding of sheet metal by Gabriel et al [18] and Tebaay et al [19]. While Gabriel et al [18] used an ytterbium-fiber laser with powers up to 82 W to clad cobalt-based powder onto Inconel 718 substrates with a thickness of 0.2 mm, Tebaay et al [19] investigated the use of a 2.5 kW diode-laser for cladding of AISI 316L powder on a DC01 sheet in either cold-rolled steel or a condition after incremental sheet-forming.…”

“…Laser systems operating in cw-mode were first used for cladding of sheet metal by Gabriel et al [18] and Tebaay et al [19]. While Gabriel et al [18] used an ytterbium-fiber laser with powers up to 82 W to clad cobalt-based powder onto Inconel 718 substrates with a thickness of 0.2 mm, Tebaay et al [19] investigated the use of a 2.5 kW diode-laser for cladding of AISI 316L powder on a DC01 sheet in either cold-rolled steel or a condition after incremental sheet-forming. The use of laser cladding for reinforcement of aluminum [20] or steel sheets [21,22] prior to forming operations has also recently attracted pronounced attention.…”

Effect of Mo on Microstructures and Wear Properties of In Situ Synthesized Ti(C,N)/Ni-Based Composite Coatings by Laser Cladding

“…As is well known, the fabrication of a wear-resistant coating on titanium alloy is one of the best methods to improve the wear-resistance [ 4 ]. As an advanced surface modification technology, laser cladding is widely employed to prepare various functional coatings on metals and their alloys [ 5 , 6 , 7 , 8 ]. It has also been proven that metal matrix composite (MMC) coatings fabricated by laser cladding can effectively enhance the tribological properties.…”