Cladding Method Research Articles

Enhancing corrosion resistance of Al-Cu/AZ31 composites synthesized by a laser cladding and FSP hybrid method

ABSTRACTHigh corrosion resistance Al-Cu powder-reinforced AZ31 Mg-based composites were produced by a laser cladding (LC) and FSP hybrid method. The microstructure characteristics, phase distribution, corrosion performance, and corrosion mechanism were ascertained using SEM, EDS, XRD and an electrochemical workstation. The composite coating of Al-Cu/AZ31 magnesium matrix composite mainly contains α-Mg solid solution, and β-Al12Mg17, AlCu4 and Al2CuMg intermetallic compounds. The intermetallic compounds did not change significantly with the proportion of Al and Cu powders. A large number of pores and microcracks in the composite coating prepared by LC were formed, whereas a sound bonding interface was observed between the LC Al-Cu coating and the matrix. In addition to the complete elimination of pores and microcracks, the microstructure of the LC composite coating became more refined, homogenized and densified due to dynamic recrystallization when it was subjected to FSP, especially FSP with pin. The sound bonding interface was not affected by FSP. The Al-Cu/AZ31 composite fabricated by LC and FSP hybrid method exhibited optimum corrosion performance. The maximum self-corrosion potential and self-corrosion current reached −0.907 V and 3.80 × 10−5 A, respectively, and 58.0% and 24.5% of the matrix, respectively. The corrosion damage behavior was dominated by pitting corrosion.

Microstructure and mechanical properties of ultrasonic assisted laser cladding Al2O3–ZrO2 ceramic coating

Al2O3–ZrO2 ceramic coatings were fabricated on titanium alloy substrate by ultrasonic assisted laser cladding. The effects of ultrasonic on the microstructure and mechanical properties of the coatings are investigated through experiments. A novel laser cladding method by ultrasonic assisted is used in this paper. In this method, ultrasonic waves are directly applied on the micro-zone of molten pool. Experimental results indicated that the grain size and mechanical properties of the coatings are improved with the ultrasonic assisted. The amount of coatings cracks are decreased due to the application of ultrasonic vibration in the laser cladding.

Study on modalities and microdefects of Al-Cu bimetallic tube by underwater explosive cladding

In this study, a screwed copper tube was cladded an aluminum tube by a new explosive cladding method. To study the modalities of the bonding interface, a light microscope was used to observe the bonding interface. To expose the weak position of the interface, a three-point bending test was conducted under extreme condition. Then the BSE (Backscattering Electron) images of the bent interfaces were obtained. Meanwhile, the EDS (Energy Dispersive Spectrometry) analyses of the melted zone were performed. The results of the light microscopic observations show that there are four bonding modalities on the interface. They can be summarized to two bonding modalities: direct bonding and bonding with the melted zone. There are no macro cracks on the interface of the bent specimens, which represents a reliable joining generally. The elastic modulus of Al-Cu bimetallic tube along the axial direction is 85.2Gpa. The BSE images, the EDS analyses and the microhardness tests show the direct bonding with some characteristics of the micro wavy interface is a pretty nice bonding pattern. The melted zone composed of CuAl2 is a weak bonding pattern, which may affect the mechanical property of the joint.

CoCrFeMnNi high‐entropy alloy powder with excellent corrosion resistance and soft magnetic property prepared by gas atomization method

AbstractTo successfully fabricate high‐entropy alloys by powder metallurgy, laser cladding, or thermal sprayed method, the high‐entropy alloy powders possessing good homogeneous microstructure are very important. However, the study on the properties of the high‐entropy alloy powder has still been lacking. In this work, an equiatomic CoCrFeMnNi high‐entropy alloy powder with spherical shape was synthesized by gas atomization method. The as‐atomized CoCrFeMnNi high‐entropy alloy powder is composed of a single face‐centered cubic solid solution phase with the particle size of 34.0 μm. Furthermore, the as‐atomized powder exhibits excellent corrosion resistance in 10 % hydrochloric acid solution to 304 L stainless steel powder, and also shows an excellent soft magnetic behavior. Therefore, the gas atomization method can be used to generate other kinds of high‐entropy alloy powders for many challenging industrial applications.

Effect of applied angle on the microstructure evolution and mechanical properties of laser clad 3540 Fe/CeO2 coating assisted by in-situ ultrasonic vibration

A novel laser cladding method assisted by in situ ultrasonic vibration is proposed in the present study. The laser cladded layer of 3540Fe/CeO2 is prepared on the 42CrMo substrate by the proposed laser cladding method. The effect of ultrasonic vibration applied angle on the microstructure evolution and mechanical properties of laser cladded coating is studied. The experimental results indicate that the application of ultrasonic vibration could improve the quality of the cladded layer. The ultrasonic vibration would refine the microstructure and homogenize the element distribution, which improves the micro-hardness of the cladded layer. The application of ultrasonic vibration is beneficial to decrease the friction coefficient and improve the wear resistant performance. The decreasing of the friction coefficient is the most obvious, when the applied angle of ultrasonic vibration is 45°.

Microstructures and Wear Resistance of Al<sub>1.5</sub>CrFeNiTi<sub>0.5 </sub>and Al<sub>1.5</sub>CrFeNiTi<sub>0.5</sub>W<sub>0.5</sub> High Entropy Alloy Coatings Manufactured by Laser Cladding

For the purpose of expanding the application scope of HEA coating manufactured on the surface modification of materials, in this work, the Al1.5CrFeNiTi0.5 and Al1.5CrFeNiTi0.5W0.5 HEA coatings were successfully manufactured using laser cladding method on SUS304. The microstructures and wear resistance of coatings are researched systematically. It is found that the W0 and W0.5 HEA coatings all exhibit the dendritic structure, which are constituted by BCC phases and Laves phases. With W element addition, the phase structures of W0.5 coating remain unchanged. W is dissolved in both two phases, but the solid solubility in Laves phase is higher compared to that in BCC phase. W0.5 coating with the highest microhardness of 848.34 HV, and the W0 coating with the microhardness of 811.45 HV, both of whose microhardness are four times more than that of SUS304 substrate. Among all samples, the W0.5 coating shows the optimal wear performance because of its larger content of hard second phase ( Laves phase).

Corrosion resistance of AlN and Fe3Al reinforced Fe-based plasma cladding layer in 3.5 wt% NaCl solution

Fe-based cladding layers were prepared via the plasma cladding method using nitrogen as protective and reactant gas. The effects of Al on the phase structure, morphology, composition, and corrosion resistance of the cladding layers were investigated. The based cladding layer consisted of α-Fe, Cr, and small amounts of CrN and FexN, whereas Fe3Al, Cr5Al8 and AlN occurred in the cladding layer with Al. Many AlN particles less than 4 μm in diameter were uniformly distributed in the cladding layer. The nitrides in the cladding layer could accelerate the formation of a passive film and increase the corrosion resistance of the cladding layer. A compact and stable passive film composed of Al2O3, Cr2O3, α-FeOOH, and Fe3O4 formed on the surface of the cladding layer with Al, which is beneficial in protecting the substrate and significantly improving the cladding layer's corrosion resistance.

Manufacturing Technology Improvement of Technology and Equipment for Preparing Steel-Copper Wire

New technology and equipment developed from the results of research work are created for producing bimetallic wire. A feature of the new technology is production of bimetallic wire by passing a steel core through molten metal. This method of obtaining bimetallic wire is called “freezing” in publications, since the external appearance of the wire obtained is similar to a form crystallized metal. Results are provided for comprehensive studies, and recommendations are aimed at increasing the level of adhesion between a coating and a core by application a thin underlayer of non-ferrous metal (copper, brass, tin, etc.) to the core surface. Use of a rotating metal brush is proposed for coating formation, i.e., a flexible tool cladding (FTC) method.

Fabrication of ZrO2(MgO)/CaAl2O4+CaAl4O7 Bilayer Structure Used for Sulfur Sensor by Laser Cladding

The ZrO2(MgO)/CaAl2O4+CaAl4O7 bilayer structure used for sulfur sensor was fabricated by the laser powder cladding (LPC) method using the MgO partially stabilized zirconia (2.7 wt% MgO-PSZ) as the substrate and the CaAl2O4 + CaAl4O7 composites as the coating material. The microstructure, phase composition and ionic conductivity of this bilayer structure were investigated for better application in the sulfur determination. The results indicated that the structure of the coating was dense and well-distributed with a thickness of 100 μm. The ionic conductivity of the ZrO2(MgO)/CaAl2O4+CaAl4O7 bilayer structure was up to 2.06 × 10−3 S·cm−1 at 850 °C that met the required ionic conductivity of ionic conductor for solid electrolyte sulfur sensor. Furthermore, the sulfur sensor Mo|Cr+Cr2O3| ZrO2(MgO)| CaAl2O4+CaAl4O7|[S]Fe| Mo was assembled used this bilayer structure and tested in carbon-saturated liquid iron at 1773 K and 1823 K. The stability and reproducibility of the sulfur sensor were satisfactory and could be used for sulfur determination in the liquid iron.

Microstructural evolution and corrosion properties of laser clad Ti-Ni on titanium alloy (Ti6Al4V)

The use of Titanium alloys (Ti6Al4V) is highly evident in applications such as aerospace, automobile, marine and petrochemical environments owing to their outstanding specific strength to weight ration and good corrosion properties. Although they have high strength useful for fabrication of engineering components and movable parts in a mechanical system, Ti6Al4V are restricted to non-friction applications as a result of their low hardness and poor wear resistance. In this work, TiNi intermetallic hard coatings on Ti6Al4V alloy via coaxial laser cladding method. The effects of laser processing parameters on morphological evolution, microhardness and electrochemical behaviour were studied. The phase present and microstructural evolution were characterized using X-ray diffractometry (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) respectively. The corrosion behaviour of the synthesized hard coating was evaluated using potentiodynamic polarization technique in 0.5M H2SO4. The microstructures showed no evidence of porosity, crack or initiation of stress.

Current Research and Development Trend of Functionally Gradient Materials

The paper summarizes the research status of international functionally gradient materials (FGM), introduces the optimization design principles, preparation processes and characteristics evaluation of functionally gradient materials, and focuses on the basic principles and process methods of the preparation process of functionally gradient materials, such as powder metallurgy. , Vapor deposition method, self-propagating high temperature synthesis method, thermal spray method, electrodeposition method, laser cladding method, etc., and look forward to the development prospects and directions of functionally gradient materials.

Thermal stability and Weatherability of Single-Layer Micron Scale Cermets Solar Selective Absorbing Coatings by Laser Cladding

The thermal stability of solar absorber coatings at high temperature is the most important challenge for solar energy photo-thermal utilization. A new one layer micrometer-size TiC/TiN-based cermet coating was designed and fabricated with laser cladding method in air. The result indicated the laser cladding could be used to obtain a TiC/TiN-Ni/Mo cermet coating with the desired optical properties. An absorptance (α) of ∼84% and a thermal emissivity (ɛ) of ∼5% at 300 K were calculated. Furthermore, the thermal stability of the coating was outstanding after heat-treatment. The absorptance and emissivity of the TiC/TiN-based cermet coating were respectively 82% and 4.1% at 650°C. The results indicated that TiC/TiN-Ni/Mo cermets are suitable for spectrally selective materials. Furthermore, the cermet coating also possesses excellent weatherability based on the test of the corrosion resistance. The results indicated that TiC/TiN-Ni/Mo cermets are suitable for spectrally selective materials. Moreover, the laser cladding was found to be an improved and novel preparation technology in the field of solar selective absorbing coatings.

Metal-polymer cladding technology for metal friction surfaces

Abstract Metal-polymer cladding technology is one of the methods to modify the working surfaces of the splined coupling of MI-26T tail transmission. The given technology implies the application of thin films of materials with certain functional properties (increased or decreased coefficient of friction, increased wear resistance, etc.). Fretting corrosion is actually one of the main problems of the above-mentioned parts. The metal-polymer cladding method is used to improve the fretting corrosion resistance of splined coupling. The utility of this method is realized by reducing the wear rate of rubbing surfaces, by improving the tribosystem service life and reliability.

LASER CLADDING OF HOT WORK TOOL STEEL (H13) WITH TIC NANOPARTICLES

In this study, titanium carbide nanoparticles (TiC) were coated on the surface of X40CrMoV51 (H13) hot work tool steel by laser coating method. Two stage laser cladding method was employed for coating processes. In the first stage, TiC powders were mixed in the phonelic resin and precoated at 50 µm thickness on the surface of steel substrate under vacuum. In the second stage, laser was directed to the surface and then hard coating layers were obtained on the steel surfaces. A CO2 laser with 2000 W power was operated at continuous-wave mode in the experiments. All laser cladding processes were performed under N2 atmosphere and various laser powers were selected to show the effect of laser power on the quality of coated steel surfaces. The morphology and phase structures were examined by scanning electron microscopy, Xray spectroscopy and optic microscope, respectively. The hardness of coating layers and bonding strength was defined with micro hardness tests and scratch test. The thickness of the coatings layers were measured in the range of 15-130 µm depending on laser powers. It is seen that crack-free, smooth and homogenous coating layers can be obtained at 237 W laser power. According to the hardness and micro-scratch tests results, hardness was improved significantly, and all coating layers had a good metallurgical strength to the substrate.

Experimental investigation and FEM analysis of laser cladding assisted by coupled field of electric and magnetic

A novel laser cladding method assisted by the coupled field of DC electric and alternating magnetic is proposed in this paper. The effects of the coupled field on the properties of the cladding coating and the flow of the molten pool are explored through experiments and finite element simulation. The experimental and simulation results show that the grain structure and the wear resistance of the cladding coating are improved under the effect of the electric and magnetic coupled field. The multiple stirring eddies appear inside the molten pool after adding the coupled field, and the fluidity of the molten pool is promoted.

Formation and properties of a Zr-based amorphous coating by laser cladding

(Zr0.53Al0.1Ni0.05Cu0.3Ti0.02)99Y1 (at%) coating with amorphous layer of about 180 μm thick was prepared on a steel substrate by using laser cladding method. The coating is compact and shows good metallurgical bonding with substrate. The microstructure, microhardness and corrosion behavior along the depth from the coating surface to the substrate were investigated. It is found that a gradient structure consisted of amorphous surface layer, amorphous–crystalline transitional layer and substrate is formed after the laser cladding. The microhardness and corrosion behavior exhibit variation with the microstructural evolution at different depths from the coating surface. The microhardness and corrosion resistance in 3.5 wt% NaCl solution of the amorphous surface layer are comparable to those of the as-cast Zr-based BMG with the same composition, and higher than those of the steel substrate.

Microstructure investigation of Inconel 625 coating obtained by laser cladding and TIG cladding methods

The purpose of this study was to investigate the microstructure of the Ni base Inconel 625 coatings that were fabricated on the Inconel 738 substrate with two processes of laser cladding and TIG cladding. For this purpose, single-pass samples were precipitated to obtain optimal parameters. In the laser cladding method, laser power, laser scanning rate and powder feed rate were considered as variables, and current and its type were considered as variables for the TIG method. Based on the results, using the parameters of optimum single-pass samples that were free of porosity, crack and had minor geometric dilution, coatings were applied in both methods with 50% overlap. In order to microstructural, elemental and phasic characterization, field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used. Based on the results, the microstructure of coatings from surface to interface of coating/substrate consists of coaxial, columnar and cellular structure dendrites, respectively, and the laser coating has a finer microstructure due to the higher cooling rate. In addition, the austenite, carbide and Laves phases were observed in both coatings.

Underwater superoleophobic stainless steel mesh fabricated by laser cladding a copper foil for oil–water separation

A simple and inexpensive one-step laser cladding method is reported to make the stainless steel mesh underwater superoleophobic. The micro/nanoscale morphologies were created via cladding a copper foil onto the stainless steel mesh using the nanosecond laser marking system. The fabricated stainless steel mesh has the underwater superoleophobic property with oil contact angles greater than 150°. Based on the special wettability, the fabricated stainless steel mesh is used to separate the light oil–water mixtures, and the separation efficiencies are >98.3%.

Simulation of Compound Rolls Produced by Electroslag Remelting Cladding Method

Electroslag remelting cladding (ESRC) with a t-shape current carrying mold was adopted to make a compound roll including a working layer and mandrel. A comprehensive coupled transient model was established to reveal the basic phenomena of electromagnetic fields, flow fields, temperature fields, and multiphase flow. Meanwhile, the movement of the mandrel and working layer relative to the slag pool was simulated by dynamic mesh technology to reveal the interface bonding mechanism. The mechanism is as follows: The temperature of the mandrel increases and the mandrel melts slightly when the mandrel passes through the slag pool. The fusion layer is a mixture of molten steel of mandrel and working layer that is the connector between the mandrel and the working layer. Therefore, the interface bonding quality is dependent on a fusion layer that is affected by the voltage/power. The investigation indicates that the fusion layer thickness is between 2 and 4 mm in the condition of 40 V that benefits from obtaining a good interface bonding quality.

High temperature spectral selective TiC-Ni/Mo cermet-based coatings for solar thermal systems by laser cladding

Thermal instability and quite high infrared emissivity at high temperature is one of the great challenges in the development of concentration solar power (CSP). Herein, a new single layer multi-scaled nanostructured TiC-Ni/Mo cermet-based spectral selective coating fabricated by the laser cladding method on stainless steel at atmospheric pressure are explored in this study. This method helps to attain the desired coating roughness which the solar absorptance of ∼86.2% has been experimentally measured and thermal emissivity of ∼4.2% at 300 K was calculated. After anneal at 600 °C for 200 h in air, the coating still showed a low thermal emissivity of ∼4.7% and a high absorptance of ∼84.7%. A high selective receiver efficiency of ∼82.0% has been achieved for laser cladding coatings. This low thermal emissivity and high solar absorptance was got by a single laser cladding layer having sub-micron surface roughness using fractal nanostructure with characteristic metal particle sizes in the range from nanoscale to microscale. These results show that the laser cladding TiC-Ni/Mo cermet-based absorbing coating would be suitable for high temperature application because it can satisfy the operating temperature of ≥600 °C in air.