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Number of results: 59
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Abstract

In this study, a theoretical model is presented to investigate the performance of a thermoelectric (TE) radiant cooling system combined with photovoltaic (PV) modules as a power supply in a building with an ambient temperature reaching more than 45ºC. The combined system TE/PV performance is studied under different solar radiation by using the hourly analysis program and photovoltaic system software. The thermal and electric characteristics of TE are theoretically investigated under various supplied voltages using the multi-paradigm programming language and numerical computing environment. Also, a theoretical analysis of heat transfer between the TE radiant cooling system and an occupied zone from the side, and the other side between the TE radiant cooling system and duct zone is presented. The maximum power consumption by TE panels and building cooling load of 130 kW is predicted for May and June. The 145 units of PV panels could provide about 50% of the power required by TE panels. The thermal and electric characteristics of TE panels results show the minimum cold surface temperature of 15ºC at a supplied voltage between 6 V and 7 V, and the maximum hot surface temperature of 62ºC at a supplied voltage of 16 V. The surface temperature difference between supplied current and supplied power increases as supplied voltage increases. At a higher supplied voltage of 16 V, the maximum surface temperature difference between supplied current, and supplied power of 150ºC, 3.2 A, and 48 W, respectively. The cooling capacity increases as supplied voltage increases, at a surface temperature difference of –10ºC and supplied voltage of 16 V, the maximum cooling capacity is founded at about 60 W. As supplied voltage decreases the coefficient of performance increases. The maximum coefficient of performance is about 5 at the surface temperature difference of –10ºC and supplied voltage of 8 V.
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Authors and Affiliations

Israa Ali Abdulghafor
1
Mohannad Jabbar Mnati
1

  1. Middle Technical University, Institute of Technology Baghdad, Al-Za’franiya, 10074, Baghdad, Iraq
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Abstract

Shell and tube heat exchangers are commonly used in a wide range of practical engineering. The key issue in such a system is the heat exchange between the hot and cold working media. An increased cost of production of these devices has forced all manufacturing companies to reduce the total amount of used materials by better optimizing their construction. Numerous studies on the heat exchanger design codes have been carried out, basically focusing on the use of fully time-dependent partial differential equations for mass, momentum, and energy balance. They are very complex and time-consuming, especially when the designers want to have full information in a full 3D system. The paper presents the 1D mathematical model for analysis of the thermal performance of the counter-current heat exchanger comprised of mixed time-dependent and time-independent equations, solved by the upwind numerical solution method, which allows for a reduction in the CPU time for obtaining the proper solution. The comparison of numerical results obtained from an in-house program called Upwind Heat Exchanger Solver written in a Fortran code, with those derived using commercial software package ASPEN, and those obtained experimentally, shows very good agreement in terms of the temperature and pressure distribution predictions. The proposed method for fast designing calculations appears beneficial for other tube shapes and types of heat exchangers.
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Authors and Affiliations

Dariusz Kardaś
1
Izabela Wardach-Święcicka
1
Artur Grajewski
2

  1. The Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gdansk, Poland
  2. HEXONIC Sp. z o.o., Warszawska 50, 82-100 Nowy Dwór Gdanski, Poland
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Abstract

The paper presents a theoretical analysis of thermal energy storage filled with phase change material (PCM) that is aimed at optimization of an adsorption chiller performance in an air-conditioning system. The equations describing a lumped parameter model were used to analyze internal heat transfer in the cooling installation. Those equations result from the energy balances of the chiller, PCM thermal storage unit and heat load. The influence of the control of the heat transfer fluid flow rate and heat capacity of the system components on the whole system operation was investigated. The model was used to validate the selection of Rubitherm RT62HC as a PCM for thermal storage. It also allowed us to assess the temperature levels that are likely to appear during the operation of the system before it will be constructed.
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Authors and Affiliations

Jarosław Karwacki
1
Roman Kwidziński
1
Piotr Leputa
1 2

  1. The Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences, Heat Transfer Department, Fiszera 14, 80-231 Gdansk, Poland
  2. ENERGA Ciepło Ostrołeka Sp. z o.o., Celna 13, 07-410 Ostrołeka, Poland
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Abstract

The present study aims at investigating and simulating the hydrogen cycle production at low temperatures using thermochemical reactions. The cycle used in this work is based on the dissociation of water molecules depending on a copper chlorine couple. Furthermore, the proposed method uses mainly thermal energy provided by a solar thermal field. This proposed cycle differs from what is found in the literature. However, most of the thermochemical cycles for hydrogen production work at quite high temperatures which is a technical challenge. Therefore, the maximum temperature used in the present cycle is limited to 500°C. A thermodynamic analysis based on both the first and second laws is performed to evaluate the energy, exergy and efficiency of each reaction as well as the overall exergetic efficiency of the system. Furthermore, a parametric study is conducted to figure out the impact of the surrounding temperatures on the overall exergetic efficiency using commercial energy simulation software. The results show that the cycle can achieve an exergy efficiency of 30.5%.
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Authors and Affiliations

Omar Benbrika
1
Ahmed Bensenouci
1
Mohamed Tegar
1
Kamal R.A. Ismail
2

  1. Department of Mechanics, Amar Telidji University of Laghouat, B.P. 37G Laghouat 03000, Algeria
  2. University of Campinas, Sao Paulo 13083-970, Brazil
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Abstract

The energy sector is a majorarea that is responsible for the country development. Almost 40% of the total energy requirement of an EU country is consumed by the building sector and 60% of which is only used for heating and cooling requirements. This is a prime concern as fossil fuel stocks are depleting and global warming is rising. This is where thermal energy storage can play a major role and reduce the dependence on the use of fossil fuels for energy requirements (heating and cooling) of the building sector. Thermal energy storage refers to the technology which is related to the transfer and storage of heat energy predominantly from solar radiation, alternatively to the transfer and storage of cold from the environment to maintain a comfortable temperature for the inhabitants in the buildings by providing cold in the summer and heat in the winter. This work is an extensive study on the use of thermal energy storage in buildings. It discusses different methods of implementing thermal energy storage into buildings, specifically the use of phase change materials, and also highlights the challenges and opportunities related to implementing this technology. Moreover, this work explains the principles of different types and methods involved in thermal energy storage.
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Authors and Affiliations

Priyam Deka
1
Andrzej Szlęk
1

  1. Silesian University of Technology, Faculty of Energy and Environmental Engineering, Konarskiego 18, 44-100, Gliwice, Poland
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Abstract

An analysis of the methods used in Bulgaria for estimating CO2, SO2 and dust emissions has been conducted. The first methodology, which is officially used by all energy auditors at the Agency for Sustainable Energy Development targets the energy efficiency of combustion devices installed mainly at industrial enterprises. The second methodology, used by the Ministry of Environment and Water, is more comprehensive and can be applied to thermal power plants, small combustion plants as well as industrial systems. In recent years, many projects related to energy efficiency and renewable energy projects, including hydrogen technologies, which require an assessment of reduced greenhouse gas emissions, have been implemented as a priority. The use of reliable and accurate methods is essential in the assessment of greenhouse emissions. A novel methodology, based on stoichiometric equations of the combustion process for solid, liquid and gaseous fuels has been proposed and comprised. This novel methodology is characterized by higher precision compared to the methods currently in place and this is achieved through calculating emissions from the combustion of energy fuels accounting for the full elemental composition of the fuel and its heating value, whereas the current commonly applied methods use only the fuel type and the carbon content. A further benefit of the proposed methodology is the ability to estimate emissions of fuels for which there is no alternative method for calculating CO2, SO2 and dust. Results of emission calculations according to the analysed methods are presented. Finally, a comparative analysis between the presented methodologies including an assessment of their accuracy and universal applicability has been made.
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Authors and Affiliations

Iliya Krastev Iliev
1
Hristo Ivanov Beloev
1
Diana Ivanova Ilieva
2
Janusz Badur
3

  1. University of Ruse, Heat, Hydraulics and Environmental Engineering, Studentska 8, 7017 Ruse, Bulgaria
  2. University of Telecommunications and Post, Akad. Stefan Mladenov 1, 1700 Sofia, Bulgaria
  3. Energy Conversion Department, Institute of Fluid Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-251 Gdansk, Poland
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Abstract

Wire and laser additive manufacturing (WLAM) can produce outstanding mechanical properties of GH3039 nickel-based superalloys. A quantitative rapid phase field model with solute trapping kinetics has been developed during the rapid solidification process, where a range of process conditions are considered in terms of thermal gradients and pulling speeds. Intergranular hot cracking is found to occur at boundaries of tilted columnar dendrite in the GH3039 nickel-based superalloys. The simulations demonstrate that the phase field model considering the interface deflection can represent the dendrite growth during additive manufacturing more realistically. With the aid of numerical simulations, it is determined that dendrite growth morphologies transform from symmetrical columnar dendrite to tilted columnar dendrite as the interface crystallographic deflection is increased, while increasing the deflection angle can lead to uneven composition of material matrix, especially at the columnar dendrite interface. Solute concentrations at the columnar dendrite interface tend to promote hot cracking in additively manufactured Ni-based superalloy.
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Authors and Affiliations

Nanfu Zong
1
ORCID: ORCID
Zheng Wang
1
ORCID: ORCID
Yang Liu
2
ORCID: ORCID
Xinghong Liang
1
ORCID: ORCID
Tao Jing
1
ORCID: ORCID

  1. Tsinghua University, Ministry of Education, School of Materials Science and Engineering, Key Laboratory for Advanced Materials Processing Technology, Beijing 100084, China
  2. Jiangsu Changqiang Iron and Steel Corp., Ltd., Jiangsu 214500, China
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Abstract

A Si-Fe-Al ternary oxide-based micropowder coating was used to prevent the formation of a Zn coating on steel during the hot-dip Zn galvanizing process to reduce the welding fume and defects generated during the welding of Zn-galvanized steel. The composition ratio of the oxide powder was optimized and its microstructure and weldability were evaluated. The optimized oxide coating was stable in the hot-dip galvanizing bath at 470°C and effectively inhibited the formation of Zn coating. The Zn residue could be easily removed with simple mechanical impact. The proposed coating reduced Zn fume and prevented the residual Zn from melting in the weld bead during high-temperature welding, thus reducing the number of welding defects. The results indicated that this pretreatment can simplify the manufacturing process and shorten the process time cost-effectively.
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Authors and Affiliations

Seong-Min So
1
Ki-Yeon Kim
1
Il-Song Park
1
ORCID: ORCID
Seok-Jae Lee
1
ORCID: ORCID
Dong-Jin Yoo
2
Yeon-Won Kim
3
ORCID: ORCID
Min-Suk Oh
1
ORCID: ORCID

  1. Jeonbuk National University, Division of Advanced Materials Engineering, Jeonju, Republic of Korea
  2. Jeonbuk National University, Department of Energy Storage/Conversion Engineering Of Graduate School, Department of Life Science, Hydrogen and Fuel Cell Research Center, Jeonju, Republic of Korea
  3. Mokpo National Maritime University, Division of Marine Mechatronics, Mokpo, Republic of Korea
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Abstract

Fusion welding of Ti-Cu is difficult because of big difference of melting points and formation of brittle intermetallic compounds. Friction stir welding is carried out by solid-state joining, thermo-mechanical stirring, and friction heat. Ti-Cu FSW dissimilar welding can supply a very sound joint area with a few intermetallic compounds. Optimized welding process conditions are essential to obtain suitable microstructure and mechanical properties of welded zones. Different welding speeds affect the evolution of microstructure and mechanical properties due to changes of input heat and internal stored deformation energy. The correlation of microstructure and mechanical properties of Ti-Cu welded zone according to welding speeds were investigated and analyzed. As the higher the welding speed, the lower the heat input and the lower the temperature rise. Ti-Cu 75 has the smallest grain size at 13.9 μm, but the optimum mechanical properties and the integrity of welding were shown in Ti-Cu 50.
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Authors and Affiliations

Yong-Jae Lee
1
ORCID: ORCID
Won-Ki Jeong
1
Seung-Jun Lee
2
Hidetoshi Fujii
3
Se Eun Shin
1
Dong-Geun Lee
1
ORCID: ORCID

  1. Sunchon National University, Department of Materials Science and Metallurgical Engineering, Suncheon, 57922, Republic of Korea
  2. Korea Polytechnic University, Department of Advanced Materials Engineering, Siheung, 15073, Republic of Korea
  3. Osaka University, Joining and Welding Research Institute, Osaka 567-0047, Japan
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Abstract

A TiC-Mo 2C-WC-Ni alloy cermet was fabricated by high-energy ball milling (HEBM) and consolidation through spark plasma sintering. The TiC-based powders were synthesized with different milling times (6, 12, 24, and 48 h) and subsequently consolidated by rapid sintering at 1300°C and a load of 60 MPa. An increase in the HEBM time led to improved sinterability as there was a sufficient driving force between the particles during densification. Core-rim structures such as (Ti, W)C and (Ti, Mo)C (rim) were formed by Ostwald ripening while inhibiting the coarsening of the TiC (core) grains. The TiC grains became refined (2.57 to 0.47 µm), with evenly distributed rims. This led to improved fracture toughness (11.1 to 14.8 MPa·m 1/2) owing to crack deflection, and the crack propagation resistance was enhanced by mitigating intergranular fractures around the TiC core.
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Authors and Affiliations

Jeong-Han Lee
1
ORCID: ORCID
Jae-Cheol Park
1
ORCID: ORCID
Hyun-Kuk Park
1
ORCID: ORCID

  1. Automotive Materials & Component R&D Group, Korea Institute of Industrial Technology, 6, Cheomdan-gwagiro 208-gil, Buk-gu, Gwangju, 61012, Korea
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Abstract

The mechanical response of interpenetrating co-continuous composite Al-Si12/SiC3D was described for uniaxial tension and compression. The internal structure of the IPC was examined by optical microscopy and micro-CT. The apparent density and Young’s modulus were assessed theoretically and experimentally. Uniaxial tensile tests were performed using the prismatic samples of dimensions 1 mm × 2 mm × 30 mm. Cylindrical samples of diameters ϕ = 5 mm and height h = 10 mm were subjected to quasi-static uniaxial compressive loading. During tests, the side surfaces of the specimen were observed using a digital image correlation system (DIC) to find strain fields and to monitor the surface cracks development in the complex internal microstructure of the IPC.
The analyzed two-phase ICP was manufactured using ceramic foam SiC infiltrated by alloy Al-Si12. This material finds application in cosmic, airplane, or automobile industries, due to their excellent tribological, heat distribution, and ballistic properties.
Obtained results show different modes of microcracking and fracture of cylindrical and prismatic samples. They indicate the substantial influence of the ceramic skeleton on the behavior of the IPC under uniaxial states of loading. Different modes of damage related to the tension or compression loading were described in detail. The results can find application in the designing process of modern co-continuous IPCs and further development of the numerical models of degradation processes.
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Authors and Affiliations

D. Pietras
1
T. Sadowski
1
M. Boniecki
2
E. Postek
3

  1. Lublin University of Technology, 20-618 Lublin, 38D Nadbystrzycka Str., Poland
  2. Łukasiewicz Research Network, Institute of Microelectronics and Photonics , 02-668 Warsaw, Poland
  3. Institute of Fundamental Technological Research, Polish Academy of Sciences, 02-106 Warsaw, Poland
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Abstract

This study aimed to develop Fe/Al multilayered metallic/intermetallic composites produced by hot pressing under an air atmosphere. Analyses were carried out on the composite plates made up of alternatively situated sheets of AA1050 aluminum alloy and DN04 low carbon steel, which were annealed at 903 K for 2, 5, and 10 h. Annealing was performed to obtain reaction layers of distinct thickness. The samples were examined using X-Ray diffraction and scanning and transmission electron microscope equipped with an energy-dispersive X-Ray spectrometer. To correlate the structural changes with mechanical properties, microhardness measurements in near-the-interface layers were performed. All the reaction layers grew with parabolic kinetics with η-Al5Fe2 intermetallic phase as the dominant component. After annealing for 5 and 10 hours, a thin sublayer of θ-Al13Fe4 phase was also detected.
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Authors and Affiliations

W. Kowalski
1
ORCID: ORCID
H. Paul
1
ORCID: ORCID
I. Mania
1
ORCID: ORCID
P. Petrzak
1
ORCID: ORCID
P. Czaja
1
ORCID: ORCID
R. Chulist
1
ORCID: ORCID
A. Góral
1
ORCID: ORCID
M. Szlezynger
1
ORCID: ORCID

  1. Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Str., 30-059 Krakow, Poland
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Abstract

In this study, the bio state of the alloy produced in the modified metal injection system was monitored after sintering. A new system operating with high gas pressure, far from the traditional injection model, has been established for material production. In this system, 316L stainless steel powders were molded using a PEG/PMMA/SA polymer recipe. During molding, approximately 60% 316L and 40% binder by volume were used. The samples obtained were sintered at different temperatures (1100-1300°C) after de-binding. Density measurement (Archimedes) and hardness tests (HV1) of the samples were measured as 6.74 g/cm3 and ~285 HV1, respectively. A potentiodynamic corrosion test was applied to monitor the effect of the amount of oxide in the structure of the 316L stainless steel produced. Corrosion tests were carried out in artificial body solutions. The corrosion rate was measured at the level of 17.08×10–3 mm/y. In terms of biocompatibility, a cytotoxicity test was applied to the samples and the life course of the bacteria was monitored. For the 316L alloys produced, the % vitality reached approximately 103%.
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Authors and Affiliations

Bünyamin Çiçek
1
Yavuz Sun
2
ORCID: ORCID

  1. Hitit University, Vocational School of Technical Sciences, Machine and Metal Technologies Department, Corum, Turkey
  2. Karabuk University, Engineering Faculty, Turkey
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Abstract

Impacts of precursor solution recipe, processing parameters, and pellet thickness on the lithium ionic conductivity of the ceramic materials with perovskite structure of Li 0.3La 0.57TiO 2 0.3La 0.57TiO 2 0.3La 0.57TiO 22 (i.e., TiO 2 sol) and then Li+ and La+ were added to the colloidal TiO 2 was on the order of 10-5 S/cm. It also showed that the temperatures corresponding to a full decomposition for Li 0.3La 0.57TiO 2 is about 750°C and materials start forming perovskite structure when temperature reaches about 900°C and the lithium ionic conductivity gains about 21% increase when the pellet thickness is reduced to about ¼.
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Authors and Affiliations

C.K. Rhee
1
ORCID: ORCID
Y.B. Chun
1
ORCID: ORCID
S.H. Kang
1
ORCID: ORCID
W.W. Kim
1
ORCID: ORCID
G. Cao
2

  1. Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea
  2. University of Washington, Seattle, WA 98195, USA
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Abstract

Azo dye is widely used in the textile industry since it is cost effective and simple to use. However, it becomes a continuous source of environmental pollution due to its carcinogenicity and toxicity. Various methods had been used to remove the azo dye in solution. One of the famous and frequently used is the Fenton process. The Fenton process is one of the advanced oxidation processes where iron catalysed hydrogen peroxide to generate hydroxyl radical. Treating azo dyes in solution requires a catalyst to enhance the process of degradation. Herein, high entropy alloys (HEAs) have been proposed as a catalytic material to enhance the performance of Fenton process for azo dye degradation. HEAs have been reported as a promising catalyst due to its high surface area. The higher the number of active sites, the higher the rate of azo dye degradation as more active sites are available for adsorption of azo dyes. The results have shown that HEAs can be used as a catalyst to fasten the Fenton reaction since the degradation time is proven to be shorter in the presence of HEAs. The method derived from the result of this study will contribute in treating azo dyes for wastewater management in the Fenton process.
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Authors and Affiliations

N.H.A. Hassan
1
ORCID: ORCID
N.S.M. Nasir
1
ORCID: ORCID
S.N.A. Rahman
1
ORCID: ORCID
A.R. Irfan
2 3
ORCID: ORCID
N.H. Nordin
1
ORCID: ORCID

  1. International Islamic University Malaysia, Department of Manufacturing and Materials Engineering, Jalan Gombak, 53100 Kuala Lumpur, Malaysia
  2. Universiti Malaysia Perlis, Faculty of Mechanical Engineering Technology, Perlis, Malaysia
  3. Universiti Malaysia Perlis, Center of Excellence Geopolymer and Green Technology (CEGeoGTech), Perlis, Malaysia
Keywords Steelmaking dust
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Abstract

In this study, a research was conducted to recover metallic zinc and pig iron and to improve the purity and the recovery rate through a reduction process for zinc and iron in the byproducts that are generated after steelmaking dust treatment. As the result of the calcination, it was confirmed that Cl (6.06%) and K (3.37%) decreased to Cl (2.75%) and K (0.22%), respectively. For the zinc powder that was recovered with reaction temperature of 1100°C, reaction time of 4 hours, and argon gas of 1L/min as the optimal conditions. The measurement for the purity of zinc was 99.8% and the recovery rate was 92.14%. The melt reduction for recovering pig iron from the residue was reacted under reaction temperature of 1600°C, flux composition (CaO:SiO2) of 1:1, and reducing agent infusion ratio (residue: C) of 14:1, and the pig iron was measured to have a purity of 87.7% and a recovery rate of 91.81%.
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Authors and Affiliations

Jei-Pl Wang
1
ORCID: ORCID

  1. Pukyong National University, Department of Metallurgical Engineering, Department of Marine Convergence Design Engineering (Advanced Materials Engineering), Busan 48513, Korea
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Abstract

Surface melting and alloying of Copper-Nickel (Cupronickel) alloy by preplacing aluminum powder and using tungsten inert gas process (TIG) in shielded atmosphere of argon gas were investigated. Surface melting resulted in the formation of a fairly porous dendritic microstructure. Surface alloying with aluminum resulted in the formation of Al 2Cu and Al 4Cu 9 intermetallic compounds along with Cu-rich matrix and unstable martensitic structure. Surface melting reduced the hardness from 140 HV 0.1 (substrate) to 70 HV 0.1, mainly due to the loss of cold work effect of the initial substrate. On the other hand, surface alloyed zone showed a hardness of 300 HV 0.1, mainly due to the formation of intermetallic compound. Tafel polarization results indicated improvement in corrosion resistance of cupronickel alloy after surface melting and alloying.
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Authors and Affiliations

Fatemeh Koeini
1
ORCID: ORCID
Mahmoud Heydarzadeh Sohi
1
ORCID: ORCID
Parham Pirayesh
2
ORCID: ORCID

  1. University of Tehran, College of Engineering, School of Metallurgy and Materials Engineering, Tehran, Iran
  2. Islamic Azad University, Faculty of Engineering, Department of Metallurgy and Materials, Karaj Branch, Karaj, Iran
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Abstract

The effect of plasma-radical change on the surface properties of Zn-Mg-Al ternary-alloy-coated steel sheets during atmospheric-pressure (AP) plasma treatment using different process gases: O 2, N 2, and compressed air was investigated. The plasma-induced radicals promoted the formation of chemical particles on the surface of the Zn-Mg-Al coating, thereby increasing the surface roughness. The surface energy was calculated using the Owen-Wendtgeometric equation. Contact angle measurements indicated that the surface free energy of the alloy sheets increased upon AP plasma treatment. The surface properties of the Zn-Mg-Al coating changed more significantly in the order air > O 2 > N 2 gas, indicating that the plasma radicals facilitated the carbonization and hydroxylation of the Mg and Al components during the AP plasma treatment.
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Authors and Affiliations

Chang-U Jeong
1
Jae-Hyeon Kim
1
Je-Shin Park
1
ORCID: ORCID
Min-Su Kim
2
ORCID: ORCID
Sung-Jin Kim
3
ORCID: ORCID
Min-Suk Oh
1
ORCID: ORCID

  1. Jeonbuk National University, Division of Advanced Materials Engineering, Jeonju, Republic of Korea
  2. Korea Institute of Industrial Technology, Gimje, Republic of Korea
  3. Sunchon National University, Department of Advanced Materials Engineering, Sunchon, Republic of Korea
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Abstract

An attempt has been made to synthesize the aluminium based ex-situ (Al-SiC) and in-situ (Al-TiB2) formed metal matrix composites with varying weight percentage of reinforcement contents such as 4wt.%, 6wt.% and 8wt.%. Synthesized composites were subjected to a cold extrusion process followed by heat treatment according to the ASTM B 918-01 standards. The mechanical properties of in-situ composites were evaluated as per the ASTM guidelines and compared with ex-situ formed composites and base metal properties. Superior properties were noticed in the in-situ formed composites and the mechanical properties such as yield strength, Ultimate tensile strength (UTS) and Hardness for both ex-situ and in-situ composites were found to increase with increasing the reinforcement addition. Cold extruded Al-8 wt.% SiC composite properties such as hardness, yield strength and UTS are 87 RB, 152 MPa, 216 MPa respectively. Whereas, for Al-8 wt.% TiB2 composite, the corresponding properties are 94 RB, 192 MPa, 293 MPa. The morphology of the composites is analysed by Optical and Scanning Electron Microscopic (SEM) whereas presence of reinforcement particles such SiC and TiB2 along with intermetallic phases Mg2Si and Al5FeSi are confirmed by EDX, XRD and Element Mapping analyses.
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Authors and Affiliations

B. Gobalakrishnan
1
C. Rajaravi
2
Gobikrishnan Udhayakumar
3
P.R. Lakshminarayanan
4

  1. CARE College of Engineering, Department of Mechanical Engineering, Trichy-620 009, Tamil Nadu, India
  2. Hindusthan College of Engineering and Technology, Coimbatore – 641 032, Tamilnadu, India
  3. Sona College of Technology, Department of Mechanical Engineering, Salem – 636 005, Tamil Nadu, India
  4. Annamalai University, Department of Manufacturing Engineering, Annamalai Nagar-608 002, Tamil Nadu, India
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Abstract

Cu-Sn alloys have been known as bronze since ancient times and widely used as electrode materials, ornaments, tableware and musical instruments. Cu-22Sn alloy fabrication by hot forging process is a Korean traditional forged high-tin bronze. The tin content is 22 percent, which is more than twice that of bronze ware traditionally used in China and the West. Copper and tin have a carbon solubility of several ppm at room temperature, making Cu-Sn-C alloys difficult to manufacture by conventional casting methods. Research on the production of carbon-added copper alloys has used a manufacturing method that is different from the conventional casting method. In this study, Cu-22Sn-xC alloy was fabricated by mechanical alloying and spark plasma sintering. The carbon solubility was confirmed in Cu-Sn alloy through mechanical alloying. The lattice parameter increased from A0 to C2, and then decreased from C4. The microstructural characteristics of sintered alloys were determined using X-ray diffraction and microscopic analysis. As a result of comparing the hardness of Cu-22Sn alloys manufactured by conventional rolling, casting, and forging and Cu-22Sn-xC alloy by sintered powder metallugy, B0 sintered alloy was the highest at about 110.9 HRB.
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Authors and Affiliations

Gwanghun Kim
1
ORCID: ORCID
Jungbin Park
1
ORCID: ORCID
Seok-Jae Lee
1
ORCID: ORCID
Hee-Soo Kim
2
ORCID: ORCID

  1. Jeonbuk National University, Division of Advanced Materials Engineering, 567 Baekje-daero, Deokjin-gu, Jeonju 54896, Republic of Korea
  2. Chosun University, Department of Materials Science and Engineering, 309 Pilmun-daero, Dong-gu, Gwangju 61452, Republic of Korea
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Abstract

The paper presents a summary of research on the possibility of influencing the state of residual stresses in railway rails by changing the pass design of vertical and horizontal straightener rollers and optimising their distribution on the rail perimeter. The presented results are devoted to the influence of profiled rollers on the level of residual stresses. A wide range of theoretical considerations were carried out based on the use of the finite element method using the commercial Forge software package. In order to verify the results of the theoretical considerations most reliably, a series of “in situ” experiments were conducted in industrial conditions on an existing production line. The tests were carried out on 120 meters long 60E1 railway rails. A significant reduction in the level of residual stresses compared to the standard requirements was achieved.
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Authors and Affiliations

S. Żak
1
ORCID: ORCID
D. Woźniak
2
ORCID: ORCID

  1. ArcelorMittal Poland S.A., Al. Józefa Piłsudskiego 92, 41-300 Dąbrowa Górnicza, Poland
  2. Institute for Ferrous Metallurgy, ul. Karola Miarki 12, 44-100 Gliwice, Poland
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Abstract

The effects of different types of balls on spark plasma sintering (SPS) characteristics of high energy ball milled Ti-48wt% Al-4wt% Nd powders were investigated. After ball milling with STS balls and zirconia balls at 800 rpm for 3 h in argon atmosphere, both powders showed shape factors of about 0.8, but their average powder sizes differed respectively at approximately 11 µm and 5 µm. From XRD results, only the peaks of pure Ti, Al and Nd were detected in both powders. The obtained Ti-Al-Nd powders were consolidated by SPS technique at 1373 K for 15 min under a pressure of 50 MPa in vacuum, resulting in high density over 99%. EDS and XRD analyses indicated the formation of binary phases such as TiAl3, TiAl, Ti3Al5, and NdAl3 after SPS in both cases of STS and zirconia balls, while the ternary Ti-Al-Nd phase was detected only in the case of zirconia balls. The size of second phases was slightly smaller in the case of zirconia balls. The microhardness of the sample was 790 Hv with zirconia balls and 540 Hv with STS balls.
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Authors and Affiliations

Hyunseung Lee
1
ORCID: ORCID
Hoseong Rhee
1
ORCID: ORCID
Sangsoo Lee
2
ORCID: ORCID
Si Young Chang
1
ORCID: ORCID

  1. Korea Aerospace University, Department of Materials Science and Engineering, Goyang, Korea
  2. Korea Aerospace University, Advanced Materials Research Institute, Goyang, Korea
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Abstract

The austenitic stability and strain-induced martensitic transformation behavior of a nanocrystalline FeNiCrMoC alloy were investigated. The alloy was fabricated by high-energy ball milling and spark plasma sintering. The phase fraction and grain size were measured using X-ray diffraction. The grain sizes of the milled powder and the sintered alloy were confirmed to be on the order of several nanometers. The variation in the austenite fraction according to compressive deformation was measured, and the austenite stability and strain-induced martensitic transformation behavior were calculated. The hardness was measured to evaluate the mechanical properties according to compression deformation, which confirmed that the hardness increased to 64.03 HRC when compressed up to 30%.
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Authors and Affiliations

Jungbin Park
1
ORCID: ORCID
Junhyub Jeon
1
ORCID: ORCID
Namhyuk Seo
1
ORCID: ORCID
Gwanghun Kim
1
ORCID: ORCID
Seung Bae Son
1
ORCID: ORCID
Jae-Gil Jung
1
ORCID: ORCID
Seok-Jae Lee
1
ORCID: ORCID

  1. Jeonbuk National University, Research Center for Advanced Materials Development, Division of Advanced Materials Engineering, Jeonju 54896, Republic of Korea

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