scholarly journals Porous APS YSZ TBC Manufactured at High Powder Feed Rate (100 g/min) and Deposition Efficiency (70%): Microstructure, Bond Strength and Thermal Gradients

2022 ◽  
Author(s):  
Rogerio S. Lima
Keyword(s):  
Bond Strength ◽  
Feed Rate ◽  
Laser Power ◽  
Production Efficiency ◽  
Deposition Efficiency ◽  
Spray Parameters ◽  
Air Plasma ◽  
Powder Feed Rate ◽  
High Enthalpy ◽  
Powder Feed

AbstractThere is a strong driving force to improve the production efficiency of thermal barrier coatings (TBCs) manufactured via air plasma spray (APS). To address this need, the high-enthalpy APS torch Axial III Plus was employed to successfully manufacture TBCs by spraying a commercial YSZ feedstock at powder feed rate of 100 g/min using an optimized set of N2/H2 spray parameters; which yielded an impressive YSZ deposition efficiency (DE) value of 70%. This exact same set of optimized spray parameters was used to manufacture the same identical YSZ TBC (over ~160 µm-thick bond-coated substrates) but at two distinct YSZ thickness levels: (i) ~420 µm-thick and (ii) ~930 µm-thick. In spite of the high YSZ feed rate and DE levels, the YSZ TBC revealed a ~14% porous (conventional looking) microstructure, without segmented cracking or horizontal delamination at both thickness levels. The bond strength values measured via the ASTM C633 standard for the ~420 µm-thick and ~930 µm-thick YSZ TBCs were ~13.0 and ~11.6 MPa (respectively); which are among at the upper end values reported in the literature. After the first objective was attained, the second key objective of this work was to evaluate the thermal insulating effectiveness of these two as-sprayed YSZ TBCs. To achieve this objective, a thermal gradient laser-rig was employed to generate a temperature reduction (ΔT) along the TBC-coated coupons under different laser power levels. These distinct laser power levels generated YSZ TBC surface temperatures varying for 1100 to 1500 °C, for the ~420 µm-thick YSZ TBC, and from 1100 to 1680 °C YSZ TBC ~930 µm-thick YSZ TBC. The respective ΔT values for both TBCs are reported. The results of this engineering paper are promising regarding the possibility of improving considerably the manufacturing efficiency of industrial quality conventional-looking porous YSZ TBCs, by using a high-enthalpy N2-based APS torch. This is the first paper published in the open literature showing R&D results of coatings manufactured via the Axial III Plus APS torch.

Multi-Objective Optimisation of Laser Deposition of Metal Matrix Composites for Surface Coating Using Principal Component Analysis

2018 ◽  
Vol 40 ◽  
pp. 9-21 ◽  
Author(s):  
Peter Kayode Farayibi
Keyword(s):  
Feed Rate ◽  
Surface Coating ◽  
Laser Power ◽  
Traverse Speed ◽  
Laser Deposition ◽  
Powder Feed Rate ◽  
Multi Objective ◽  
Powder Feed ◽  
Output Characteristics ◽  
Wire Feed

Laser deposition is an advanced manufacturing technology capable of enhancing service life of engineering components by hard-facing their functional surfaces. There are quite a number of parameters involved in the process and also desirable output characteristics. These output characteristics are often independently optimised and which may lead to poor outcome for other characteristics, hence the need for multi-objective optimisation of all the output characteristics. In this study, a laser deposition of Ti-6Al-4V wire and tungsten carbide powder was made on a Ti-6Al-4V substrate with a view to achieve a metallurgical bonded metal matrix composite on the substrate. Single clads were deposited with a desire to optimise the composite clad characteristics (height, width and reinforcement fraction) for the purpose of surface coating. Processing parameters (laser power, traverse speed, wire feed rate, powder feed rate) were varied, the experiment was planned using Taguchi method and output characteristics were analysed using principal component analysis approach. The results indicated that the parameters required for optimised clad height, width, and reinforcement fraction necessary for surface coating is laser power of 1800 W, traverse speed of 200 mm/min, wire feed rate 700 mm/min and powder feed rate of 30 g/min. The powder feed rate was found to most significantly contribute 43.99%, followed by traverse speed 39.77%, laser power 15.87% with wire feed rate having the least contribution towards the multi-objective optimisation. Confirmation results showed that clad width and reinforcement fraction were significantly improved by the optimised parameters. The multi-objective optimisation procedure is a useful tool necessary to identify the process factors required to enhance output characteristics in laser processing.

Processing parameter, microstructure and hardness of Ni base intermetallic alloy coating fabricated by laser cladding

MRS Advances ◽  
2017 ◽  
Vol 2 (26) ◽  
pp. 1381-1386 ◽  
Author(s):  
Takeshi Okuno ◽  
Yasuyuki Kaneno ◽  
Takuto Yamaguchi ◽  
Takayuki Takasugi ◽  
Satoshi Semboshi ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Feed Rate ◽  
Laser Power ◽  
Alloy Coating ◽  
Intermetallic Alloy ◽  
Ingot Metallurgy ◽  
Processing Parameter ◽  
Powder Feed Rate ◽  
Cladding Layer ◽  
Powder Feed

ABSTRACTNi base intermetallic alloy coating was fabricated by laser cladding, controlling the laser power and powder feed rate. Atomized powder of the Ni base intermetallic alloy was laser-cladded on the substrate of stainless steel 304. The hardness and microstructure of the clad layers were investigated by Vickers hardness test, SEM, XRD and TEM observations. The hardness of the cladding layer was affected by the dilution with the substrate; it increased with decreasing laser power and increasing powder feed rate. By optimizing the dilution with the substrate, the cladding layer with an almost identical hardness level to that of the Ni base intermetallic alloy fabricated by ingot metallurgy was obtained. The TEM observations revealed that a very fine-sized microstructure composed of Ni3Al and Ni3V was partially formed even in the as-cladded state. After annealing, the two-phase microstructure composed of Ni3Al and Ni3V was developed in the cladding layer, resulting in enhanced hardness in the cladding layers fabricated in the majority of cladding conditions.

Modeling of Transport Phenomena in the Laser Multilayered Cladding

2009 ◽  
Author(s):  
Fanrong Kong ◽  
Radovan Kovacevic
Keyword(s):  
Feed Rate ◽  
Molten Pool ◽  
Laser Power ◽  
Steel Powder ◽  
Mass Transfer Process ◽  
Scanning Speed ◽  
Heat Radiation ◽  
Powder Feed Rate ◽  
Transient Model ◽  
Powder Feed

The present work studies the heat and mass transfer process in the laser multilayered cladding of H13 tool steel powder by numerical modeling and experimental validation. A solid-liquid-gas unified transient model was developed to investigate the evolution of temperature distribution and flow velocity of the liquid phase in the molten pool. In this model, an enthalpy-porosity approach was applied to deal with the solidification and melting occurring in the clad, and a level-set method was used to track the evolution of the molten pool free surface. Moreover, heat loss due to forced convection and heat radiation and laser heat input occurring on the top surface of deposited layer and substrate have been incorporated into the source term of governing equations. The effects of laser power, scanning speed, and powder feed rate on the dilution and height of the multilayered clad are investigated based on the numerical model and experimental measurement. The results show that increasing the laser power and powder feed rate, or reducing the scanning speed, can increase the clad height and directly influence the remelted depth of each layer of deposition. The numerical results have a qualitative agreement with the experimental measurements.

scholarly journals Optimizing the Characteristics of the Laser Hardfacing Process Parameters to Maximize the Wear Resistance of Ni-Based Hard-Faced Deposits Using the RSM Technique

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
S. Gnanasekaran ◽  
Samson Jerold Samuel Chelladurai ◽  
T. Ramakrishnan ◽  
S Sivananthan ◽  
G. Padmanaban ◽  
...  
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Process Parameters ◽  
Feed Rate ◽  
Laser Power ◽  
Travel Speed ◽  
Powder Feed Rate ◽  
Powder Feed ◽  
Rsm Technique

The nickel-based Colmonoy-5 hardfacing alloy is used to hard-face 316LN austenitic stainless steel components in fast reactors. The nominal composition (in wt%) was listed as follows: 0.01 C, 0.49 Si, 0.87 Mn, 17.09 Cr, 14.04 Ni, 2.56 Mo, 0.14 N, and balance Fe. Hardfacing is a technique of applying hard and wear-resistant materials to substrates that need abrasion resistance. The thickness of hardfacing deposit varies between 0.8 mm and 2 mm based on parameter combinations. In this study, laser hardfacing process parameters including laser power, powder feed rate, travel speed, and defocusing distance were optimized to reduce weight loss of laser hard-faced Ni-based deposit. The tribological characteristics of reactor-grade NiCr-B hard-faced deposits were investigated. The RSM technique was used to identify the most important control variables resulting in the least weight loss of the nickel-based alloy placed on AISI 316LN austenitic stainless steel. Statistical techniques like DoE and ANOVA are utilized. Changing the laser settings may efficiently track the weight loss of laser hard-faced nickel alloy surfaces. These are created using the response surface technique. The deposit produced with a laser power of 1314 W, powder feed rate of 9 g/min, travel speed of 366 mm/min, and defocusing distance of 32 mm had the lowest weight loss of 16.4 mg. Based on the F value, the powder feed rate is the major influencing factor to predict the hardness followed by power, travel speed, and defocusing distance.

Effect of Process Parameters on Laser Directed Energy Deposition of Copper

2019 ◽  
Author(s):  
Sunil Yadav ◽  
Christ P. Paul ◽  
Arackal N. Jinoop ◽  
Saurav K. Nayak ◽  
Arun K. Rai ◽  
...  
Keyword(s):  
Process Parameters ◽  
Feed Rate ◽  
Laser Power ◽  
Energy Deposition ◽  
Process Conditions ◽  
Powder Feed Rate ◽  
Track Geometry ◽  
Powder Feed ◽  
Directed Energy Deposition ◽  
Directed Energy

Abstract Laser Additive Manufacturing (LAM) is an advanced manufacturing processes for fabricating engineering components directly from CAD Model by depositing material in a layer by layer fashion using lasers. LAM is being widely deployed in various sectors such as power, aerospace, automotive etc. for fabricating complex shaped and customized components. One of the most commonly used LAM process is Directed Energy Deposition (LAM-DED) which is used for manufacturing near net shaped components with tailored microstructure, multi-materials (direct and graded) and complex geometry. This paper reports experimental investigation of LAM of Copper (Cu) tracks on Stainless Steel 304 L (SS 304L) using an indigenously developed LAM-DED system. Cu-SS304L joints find wider applications in tooling, automotive and aerospace sectors due to its combination of higher strength, thermal conductivity and corrosion resistance. However, laying Cu layers on SS304L is not trivial due to large difference in the thermo-physical properties. Thus, a comprehensive experiments using full factorial design are carried out and a number of Cu tracks were laid on SS304L substrate by varying laser power, scan speed and powder feed rate. The laid tracks are characterized for track geometry and porosity and the quality of the tracks are analyzed. Lower values of laser power and higher powder feed rate results in discontinuous deposition, while higher laser power and lower powder feed rate results in cracked deposits. Porosity is observed to vary from 6–45 % at different process conditions. Analysis of Variance (ANOVA) of deposition rate and track geometry is performed to estimate the major contributing process parameters. This study paves a way to understand effect of process parameters on LAM-DED for fabricating bimetallic joints and graded structures of Copper and SS304L.

scholarly journals Microstructure development in Laser Metal Deposition of Ti-5553

2020 ◽  
Vol 321 ◽  
pp. 03019
Author(s):  
C. Hicks ◽  
T. Konkova ◽  
P. Blackwell
Keyword(s):  
Feed Rate ◽  
Laser Power ◽  
Complex Geometry ◽  
High Strength ◽  
Metal Deposition ◽  
Manufacturing Cost ◽  
Laser Metal Deposition ◽  
Powder Feed Rate ◽  
Pronounced Increase ◽  
Powder Feed

Laser Metal Deposition (LMD) is promoting increased interest with regard to manufacturing parts of complex geometry. It is especially important with respect to manufacturing cost reductions for relatively expensive Titanium alloys. The rapid and directional cooling processes inherent with LMD produce nonhomogeneous microstructures and large residual stresses. Knowledge of the LMD process to optimise deposited microstructures is in high demand. The high-strength β-Titanium alloy, Ti-5Al-5Mo-5V-3Cr (Ti-5553), was deposited using LMD on to a heat-treated substrate of the same alloy. Two blocks of 15 x 15 x 6.4 mm3 were made with different laser power to powder feed rate ratios followed by microstructural analyses. Both blocks have almost identical geometry and density. Low ratios of laser power to powder feed rate resulted in pure β phase in the deposited layers and the re-melted material in the substrate. High ratios resulted in larger columnar β grains, the precipitation of nano-scaled α, and a pronounced increase in microhardness ≈1 mm above and below the substrate interface. This could be detrimental to the mechanical properties of the substrate and highlights the importance of the optimisation of LMD parameters.

Optimization of Thermal Spray Parameters of NiAl/Cr2C3 Coating by Taguchi Method

2019 ◽  
Vol 295 ◽  
pp. 9-14 ◽  
Author(s):  
M. Tahari ◽  
B. Luo ◽  
J. Geng ◽  
D. Jing ◽  
M. Hatami
Keyword(s):  
Wear Resistance ◽  
Thermal Spray ◽  
Feed Rate ◽  
Spray Coating ◽  
Wear Test ◽  
Thermal Spray Coating ◽  
Spray Parameters ◽  
Spray Distance ◽  
Powder Feed Rate ◽  
Powder Feed

In this study the effect of thermal spray process on wear resistance of NiAl/Cr2C3 thermal spray coating has been investigated. For this purpose the NiAl power mixed with 10 %wt. Cr2C3 powder and milled for 1 hrs at argon atmosphere. The APS parameters such as voltage (V), current (A), spray distance (mm), powder feed rate (gr/min), were optimize using a response surface methodology. For investigation effect of spray parameters on quality of coatings, the porosity and wear resistance of coatings analyzed with SEM and pin on disk wear test. Results show that increase of voltage and current are more effective other parameters. Increasing of powder feed rate and spray distance raised porosity of coatings intensively.

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