scholarly journals Hybrid Laser Deposition of Fe-Based Metallic Powder under Cryogenic Conditions

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 190 ◽  
Author(s):  
Aleksander Lisiecki ◽  
Dawid Ślizak
Keyword(s):  
Laser Cladding ◽  
Cross Sections ◽  
Energy Dispersive Spectrometer ◽  
High Hardness ◽  
Ambient Air ◽  
Laser Deposition ◽  
Influence Of Process Parameters ◽  
Cooling Conditions ◽  
Forced Cooling ◽  
Cryogenic Conditions

The purpose of this study was to demonstrate the novel technique of laser deposition of Fe-based powder under cryogenic conditions provided by a liquid nitrogen bath. Comparative clad layers were produced by conventional laser cladding at free cooling conditions in ambient air and by the developed process combining laser cladding and laser gas nitriding (hybrid) under cryogenic conditions. The influence of process parameters and cooling conditions on the geometry, microstructure, and hardness profiles of the clad layers was determined. The optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and XRD test methods were used to determine the microstructure and phase composition. The results indicate that the proposed technique of forced cooling the substrate in a nitrogen bath during the laser deposition of Fe-based powder is advantageous because it provides favorable geometry of the clad, low dilution, a narrow heat-affected zone, a high hardness and uniform profile on the cross-sections, homogeneity, and refinement of the microstructure. The influence of the forced cooling on microstructure refinement was quantitatively determined by measuring the secondary dendrite arm spacing (SDAS). Additionally, highly dispersed nanometric-sized (200–360 nm) precipitations of complex carbides were identified in interdendritic regions.

scholarly journals Hybrid Laser Deposition of Composite WC-Ni Layers with Forced Local Cryogenic Cooling

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4312
Author(s):  
Aleksander Lisiecki ◽  
Dawid Ślizak
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Heat Input ◽  
Ambient Air ◽  
Cryogenic Cooling ◽  
Laser Deposition ◽  
Dry Sliding ◽  
Tungsten Carbides ◽  
Cooling Conditions ◽  
The Matrix

The purpose of this study was to demonstrate the effect of forced and localized cooling by nitrogen vapours stream under cryogenic conditions during laser deposition of WC-Ni powder on the geometry, microstructure of clad layers and dry sliding wear resistance of the coatings. For this purpose, comparative tests were performed by conventional laser cladding at free cooling conditions in ambient air and by the developed novel process of laser deposition with additional localized cooling of the solidifying deposit by nitrogen vapours stream. Due to presence of gaseous nitrogen in the region of the melt pool and solidifying deposit, the process was considered as combining laser cladding and laser gas nitriding (performed simultaneously), thus the hybrid process. The influence of the heat input and cooling conditions on the geometrical features, dilution rate, share of carbides relative to the matrix, and the fraction share of carbides, as well as hardness profiles on cross sections of single stringer beads was analysed and presented. The XRD, EDS analysis and the sieve test of the experimental powder were used to characterize the composite WC-Ni type powder. The OM, SEM, EDS and XRD test methods were used to study the microstructure, chemical and phase composition of clad layers. Additionally, ball-on-disc tests were performed to determine the wear resistance of representative coatings under dry sliding conditions. The results indicate that the novel demonstrated technique of localized forced cooling of the solidifying deposit has advantageous effect, because it provides approximately 20% lower penetration depth and dilution, decreases tendency for tungsten carbides decomposition, provides more uniform distribution and higher share of massive eutectic W2C-WC carbides across the coating. While the conventionally laser cladded layers show tendency for decomposition of carbide particles and resolidifying dendritic complex carbides mainly M2C, M3C and M7C3 containing iron, nickel, and tungsten, and with Ni/Ni3B matrix. The quantitative relationship between heat input, cooling conditions and the carbides grain size distribution as well as carbides share in relation to the matrix was determined.

Laser cladding of Co-based metallic powder at cryogenic conditions

2019 ◽  
Vol 1 (95) ◽  
pp. 20-31
Author(s):  
A. Lisiecki ◽  
D. Ślizak ◽  
A. Kukofka
Keyword(s):  
Liquid Nitrogen ◽  
Laser Cladding ◽  
The Novel ◽  
Novel Technique ◽  
Custom Made ◽  
Nozzle Head ◽  
Forced Cooling ◽  
Liquid Nitrogen Bath ◽  
Cryogenic Conditions ◽  
Conventional Laser

Purpose: of this paper was demonstration a novel technique of laser cladding by experimentally composed Co-based metallic powder and forced cooling of the substrate by liquid nitrogen under cryogenic conditions, at the temperature -190°C, for producing clad layers with enhanced microstructure characteristic and properties. Design/methodology/approach: Technological tests of laser cladding were conducted by means of a high power fibre laser HPFL with maximum output power 3.0 kW, and six-axis robot. The experimental Co-based powder was composed for providing high abrasive wear resistance, high resistance for impact load, and also for corrosion resistance at elevated temperature. The unique and novel technique of forced cooling of the substrate was provided by immersing the specimens in the liquid nitrogen bath. The three coaxial nozzle head was designed and custom made to provide precise deposition of the powder delivered into the laser beam irradiation region. The scope of the study included tests of conventional laser cladding at free cooling in ambient air in a wide range of processing parameters, and also trials of laser cladding under cryogenic conditions. The test clad layers produced by conventional laser cladding and by the novel technique of laser powder deposition under cryogenic conditions were investigated and compared. Findings: The obtained results indicate that the novel technique of forced cooling the substrate by liquid nitrogen bath provides lower penetration depth, as well as low dilution of the clad, and also provides higher hardness of the clads. Additionally, it is possible shaping the geometry of the individual bead, providing high reinforcement and low width. Research limitations/implications: The presented results are based just on preliminary test of the novel technique of laser cladding under cryogenic conditions. Therefore, further study and detailed analyse of the influence of the cooling rate on the quality, microstructure, and properties of the deposited coatings are required. Practical implications: The study is focused on practical application of the novel technique for manufacturing of wear resistance coatings characterised with enhanced performance compared to conventional range of application of the laser cladding. Originality/value: Novel technique of laser cladding at forced cooling under cryogenic conditions was demonstrated. The powder used for cladding trials was experimentally composed (not commercially available). The experimental stand custom made was used with custom made powder feeding rate, and also with custom made coaxial nozzle head.

scholarly journals The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478 ◽  
Author(s):  
Luděk Stratil ◽  
Vít Horník ◽  
Petr Dymáček ◽  
Pavla Roupcová ◽  
Jiří Svoboda
Keyword(s):  
Oxidation Resistance ◽  
Cross Sections ◽  
Aluminum Content ◽  
Energy Dispersive Spectrometer ◽  
Oxide Dispersion Strengthened ◽  
Xrd Analysis ◽  
Al Content ◽  
Α Al2o3 ◽  
New Generation ◽  
Ods Alloy

The aim of the paper is to evaluate the effect of aluminum content on the oxidation resistance of new-generation of oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades of the alloy of chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 wt.% are prepared by mechanical alloying. The alloys are consolidated by high temperature rolling followed by heat treatment. To study the oxidation resistance the samples are isothermally aged in the air for 1 h, 4 h, 16 h and 64 h at 1200 °C. The oxidation kinetics, composition and formation mechanism of the oxide layers are analyzed. The weight gain of prepared steels is estimated. The kinetics of oxidation is studied on metallographic cross-sections of the exposed samples by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis. The oxides on the surfaces are identified by X‑ray diffraction (XRD) analysis. The Al content significantly enhances the oxidation resistance of the alloy. For a sufficiently high Al content in the alloy a compact oxide layer of α‑Al2O3 on the surface is formed, which significantly suppresses further oxidation process.

scholarly journals Analysis of the Process Parameter Influence in Laser Cladding of 316L Stainless Steel

2018 ◽  
Vol 2 (3) ◽  
pp. 55 ◽  
Author(s):  
Piera Alvarez ◽  
M. Montealegre ◽  
Jose Pulido-Jiménez ◽  
Jon Arrizubieta
Keyword(s):  
Stainless Steel ◽  
Laser Cladding ◽  
Process Parameters ◽  
Cross Sections ◽  
316L Stainless Steel ◽  
Deposition Process ◽  
Process Parameter ◽  
Optimum Process ◽  
Processing Times ◽  
Manufacturing Technologies

Laser Cladding is one of the leading processes within Additive Manufacturing technologies, which has concentrated a considerable amount of effort on its development. In regard to the latter, the current study aims to summarize the influence of the most relevant process parameters in the laser cladding processing of single and compound volumes (solid forms) made from AISI 316L stainless steel powders and using a coaxial nozzle for their deposition. Process speed, applied laser power and powder flow are considered to be the main variables affecting the laser cladding in single clads, whereas overlap percentage and overlapping strategy also become relevant when dealing with multiple clads. By setting appropriate values for each process parameter, the main goal of this paper is to develop a processing window in which a good metallurgical bond between the delivered powder and the substrate is obtained, trying simultaneously to maintain processing times at their lowest value possible. Conventional metallography techniques were performed on the cross sections of the laser tracks to measure the effective dimensions of clads, height and width, as well as the resulting dilution value. Besides the influence of the overlap between contiguous clads and layers, physical defects such as porosity and cracks were also evaluated. Optimum process parameters to maximize productivity were defined as 13 mm/s, 2500 W, 30% of overlap and a 25 g/min powder feed rate.

Laser Cladding of Alumina Material Coating: Effects on Deposition Quality

2016 ◽  
Author(s):  
Yuzhou Li ◽  
Weilong Cong ◽  
Fuda Ning ◽  
Rongxia Huang
Keyword(s):  
Laser Cladding ◽  
High Performance ◽  
Ceramic Coating ◽  
High Hardness ◽  
Alumina Ceramic ◽  
Properties Of Coatings ◽  
Surface Protection ◽  
Laser Head ◽  
Coating Methods ◽  
Input Variables

Alumina ceramic is a high performance engineering material with excellent properties, including high melting point, high hardness and brittle nature make the alumina ceramic difficult to machine and needing high cost by using conventional manufacturing methods. Coating is an important method for alumina fabrication. The excellent properties of coatings can be used for special surface protection and ceramic parts repairing. Comparing with other coating methods, laser cladding method has many good properties to overcome the drawbacks. The reported investigations on laser cladding provide little information about alumina materials for ceramic coating. In this paper, effects of different input variables of laser cladding of alumina materials for ceramic coating were studied. And this paper for the first time reported the relationship between the properties (including surface roughness, flatness and powder efficiency) and input variables such as laser power, powder feeding rate and laser head moving rate. The obtained results will be helpful to establish efficient and effective processes for ceramics coating.

scholarly journals Optimization of Ni-Based WC/Co/Cr Composite Coatings Produced by Multilayer Laser Cladding

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Andrea Angelastro ◽  
Sabina L. Campanelli ◽  
Giuseppe Casalino ◽  
Antonio D. Ludovico
Keyword(s):  
Laser Cladding ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Metallic Matrix ◽  
Optimization Procedure ◽  
High Hardness ◽  
Fatigue Properties ◽  
Metal Composite ◽  
Tungsten Carbides ◽  
Cobalt Chromium

As a surface coating technique, laser cladding (LC) has been developed for improving wear, corrosion, and fatigue properties of mechanical components. The main advantage of this process is the capability of introducing hard particles such as SiC, TiC, and WC as reinforcements in the metallic matrix such as Ni-based alloy, Co-based alloy, and Fe-based alloy to form ceramic-metal composite coatings, which have very high hardness and good wear resistance. In this paper, Ni-based alloy (Colmonoy 227-F) and Tungsten Carbides/Cobalt/Chromium (WC/Co/Cr) composite coatings were fabricated by the multilayer laser cladding technique (MLC). An optimization procedure was implemented to obtain the combination of process parameters that minimizes the porosity and produces good adhesion to a stainless steel substrate. The optimization procedure was worked out with a mathematical model that was supported by an experimental analysis, which studied the shape of the clad track generated by melting coaxially fed powders with a laser. Microstructural and microhardness analysis completed the set of test performed on the coatings.

scholarly journals Enhanced Tribological Properties of LA43M Magnesium Alloy by Ni60 Coating via Ultra-High-Speed Laser Cladding

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 638 ◽  
Author(s):  
Osama Asghar ◽  
Lou Li-Yan ◽  
Muhammad Yasir ◽  
Li Chang-Jiu ◽  
Li Cheng-Xin
Keyword(s):  
Wear Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Wear Mechanism ◽  
High Speed ◽  
Surface Engineering ◽  
Energy Dispersive Spectrometer ◽  
Wear Loss ◽  
Cross Sectional ◽  
Ultra High Speed

Laser modification techniques have been widely adopted in the field of surface engineering. Among these modified techniques, ultra-high-speed laser cladding is trending most nowadays to fabricate wear-resistant surfaces. The main purpose of this research is to provide a detailed insight of ultra-high-speed laser cladding of hard Ni60 alloy on LA43M magnesium alloy to enhance its surface mechanical properties. Multiple processing parameters were investigated to obtain the optimal result. The synthesized coating was studied microstructurally by field emission scanning electron microscopy (FESEM) equipped with an energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The microhardness and wear resistance of the Ni60 coating were analyzed under Vickers hardness and pin on disc tribometer respectively. The obtained results show that the dense Ni60 coating was fabricated with a thickness of 300 μm. No cracks and porosities were detected in cross-sectional morphology. The Ni60 coating was mainly composed of γ-Ni and hard phases (chromium carbides and borides). The average microhardness of coating was recorded as 948 HV0.3, which is approximately eight times higher than that of the substrate. Meanwhile, the Ni60 coating exhibited better wear resistance than the substrate, which was validated upon the wear loss and wear mechanism. The wear loss recorded for the substrate was 6.5 times higher than that of the coating. The main wear mechanism in the Ni60 coating was adhesive while the substrate showed abrasive characteristics.

Investigation on laser cladding high-hardness nano-ceramic coating assisted by ultrasonic vibration processing

Optik ◽  
2016 ◽  
Vol 127 (11) ◽  
pp. 4596-4600 ◽  
Author(s):  
Meiyan Li ◽  
Bin Han ◽  
Yong Wang ◽  
Lixin Song ◽  
Lanyang Guo
Keyword(s):  
Ultrasonic Vibration ◽  
Laser Cladding ◽  
Ceramic Coating ◽  
High Hardness

Cross-Sectional Nanoindentation of Alumina Thin Films Deposited by Pulsed Laser Deposition Process

2006 ◽  
Author(s):  
Sudheer Neralla ◽  
Sergey Yarmolenko ◽  
Dhananjay Kumar ◽  
Devdas Pai ◽  
Jag Sankar
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
High Hardness ◽  
Deposition Process ◽  
Laser Deposition ◽  
Cross Sectional ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Atomic Force

Alumina is a widely used ceramic material due to its high hardness, wear resistance and dielectric properties. The study of phase transformation and its correlation to the mechanical properties of alumina is essential. In this study, interfacial adhesion properties of alumina thin films are studied using cross-sectional nanoindentation (CSN) technique. Alumina thin films are deposited at 200 and 700 °C, on Si (100) substrates with a weak Silica interface, using pulsed laser deposition (PLD) process. Effect of annealing on the surface morphology of the thin films is studied using atomic force microscopy. Xray diffraction studies revealed that alumina thin films are amorphous in nature at 200 °C and polycrystalline with predominant gamma alumina phase at 700 °C.

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