ORCID Profile
0000-0002-0833-3227
Current Organisation
UNSW Sydney
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Environmental Engineering | Environmental Technologies |
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.JENVMAN.2016.11.079
Abstract: Environmental concern about automotive shredder residue (ASR) has increased in recent years due to its harmful content of heavy metals. Although several approaches of ASR management have been suggested, these approaches remain commercially unproven. This study presents an alternative approach for ASR management where advanced materials can be generated as a by-product. In this approach, titanium nitride (TiN) has been thermally synthesized by nitriding pressed mixture of automotive shredder residue (ASR) and titanium oxide (TiO
Publisher: CrossRef
Date: 2006
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 03-2017
Publisher: Trans Tech Publications, Ltd.
Date: 10-2006
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.116-117.358
Abstract: Semi-Solid metal (SSM) processing is now considered a commercially successful manufacturing route producing millions of near net shape parts per annum for the automotive industry. Although semi-solid process is currently widely used as a manufacturing process which produces near net-shape metal component, the processes those used for the preparation of semi-solid slurry still take a great deal of time, energy and money. Cup cast method – recently developed by the authors – is able to make semi-solid slurry preparation as easy as pouring water from a pitcher into drinking glass. In this method globular solid particles are prepared by controlling the turbulence and heat distribution in the melt through pouring instead of applying certain external stirring forces, in other common method. In the current study, cup cast method applied to Al-A356 alloy using simple cylinder. Vital factors of this method were optimized by investigating micro-structures.
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer London
Date: 2013
Publisher: MDPI AG
Date: 12-03-2018
DOI: 10.3390/MET8030176
Publisher: Iron and Steel Institute of Japan
Date: 2011
Publisher: Iron and Steel Institute of Japan
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 26-04-2021
Publisher: Tsinghua University Press
Date: 04-2008
Publisher: Elsevier BV
Date: 05-2023
Publisher: MDPI AG
Date: 04-11-2020
DOI: 10.3390/JCS4040166
Abstract: Recent studies have demonstrated that carbon nanomaterials have huge potential in composite applications, but there is a continuous quest for identifying the most viable technique for producing this material. In this study, the possibility of using an innovative approach for the synthesis of value-added carbon nanomaterials and green gases from end-of-life soft mattress materials (latex) was investigated. Thermogravimetric analysis (TGA) was used to determine the thermal degradation of latex. Quantitative gas analysis at three different temperatures by infrared spectroscopy (IR) suggested that small gas molecules, especially CH4, could be produced at a higher temperature. The carbon residues produced after gas analysis were characterised by XRD, SEM, TEM, XPS, and Raman spectroscopy, suggesting the possibility of direct synthesis of carbon nanomaterials from waste latex. These carbon materials have Na, Zn, Si, and K in their structure, and further study is needed for understanding the effect of these elements on composite properties. Our study demonstrated that heat treatment of waste latex at 1000 °C for 15 min produced carbon materials, which contained 7–16% S and 1.2–2% N, and gases, such as CH4, could be synthesised.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Wiley
Date: 08-2010
Publisher: Elsevier BV
Date: 12-2022
Publisher: MDPI AG
Date: 09-07-2019
DOI: 10.3390/JMMP3030055
Abstract: It is well known that stress-induced phase transformation in dual-phase steel leads to the degradation of bulk corrosion resistance properties. Predicting this behaviour in high carbon steel is imperative for designing this grade of steel for more advanced applications. Dual-phase high carbon steel consists of a martensitic structure with metastable retained austenite which can be transformed to martensite when the required energy is attained, and its usage has increased in the past decade. In this study, insight into the influence of deformed microstructures on corrosion behaviour of dual-phase high carbon steel was investigated. The generation of strain-induced martensite formation (SIMF) by residual stress through plastic deformation, misorientation and substructure formation was comprehensively conducted by EBSD and SEM. Tafel and EIS methods were used to determine corrosion intensity and the effect of corrosion behaviour on hardness properties. As a result of the static compression load, the retained austenite transformed into martensite, which lowered its corrosion rate by 5.79% and increased the dislocation density and the length of high-angle grain boundaries. This study demonstrates that balancing the fraction of the martensite phase in structure and dislocation density, including the length of high-angle grain boundaries, will result in an increase in the corrosion rate in parallel with the applied compression load.
Publisher: MDPI AG
Date: 18-11-2022
DOI: 10.3390/MET12111969
Abstract: In the present study, the isothermal decomposition of austenite to bainite in 1.0 wt% carbon, 0.21% silicon steel during the partitioning step of a quenching and partitioning (Q& P) heat treatment has been investigated in a dilatometer in the temperature range of 200 to 350 °C and compared to conventional austempering heat treatment. The bainite transformation was shortened by about 75% in the presence of pre-existing martensite (QP). The kinetics of bainite transformation is described by the well-known Avrami equation. The calculated parameter ‘n’ in the Avrami equation shows that bainite forms in the absence of pre-existing martensite (TT) at a constant nucleate rate, while in the presence of pre-existing martensite, nucleation is interface controlled. The overall bainite transformation activation energy, calculated by the Avrami equation, ranges from 64 to 110 kJ/mol. The outcomes of this investigation provide guidelines for the development of multiphase microstructures, including pre-existing martensite and bainite in high-carbon low-silicon steel, within an industrially acceptable time scale and mechanical performance.
Publisher: Iron and Steel Institute of Japan
Date: 2010
Publisher: Trans Tech Publications, Ltd.
Date: 07-2006
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.519-521.1835
Abstract: The needs for high-strength and lightweight structural materials have increased in automotive and aerospace structural applications. Semi-solid processed light alloys have satisfied these requirements because of processing advantages and significant weight reduction. Conventional semi-solid casting methods have got a wide variety of problems and difficulties. The cup-cast method that has been just developed is a novel process that make semi-solid casting as easy as pouring the water from a pitcher into a drinking glass, and avoid all the problem and difficulties of other semi-solid casting processes. Cup cast method is based on the heat and mass transfer and spherical equiaxed particles with controlling the nucleation and growth of solid particles were produced. In this study the different factor of this method was optimized by micro-structural investigation on the Al-A356 alloy. Pouring height and temperature, duration of pouring, and cup coating had played important roles in this method.
Publisher: Elsevier BV
Date: 07-2023
Publisher: Trans Tech Publications Ltd.
Date: 15-10-2006
Publisher: Springer Science and Business Media LLC
Date: 21-08-2018
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 08-2021
Publisher: Springer Science and Business Media LLC
Date: 13-01-2020
DOI: 10.1038/S41598-019-55803-6
Abstract: There is a continuous quest for discovery of a steel grade which has better properties and lower production cost. To design steel with superior properties for industrial application, it is essential to understand the effect of microstructure and engineer it to fit the purpose. In this study, a counter intuitive strategy has used to reveal the mechanism of high carbon steel with ultrahard structure. High compact force has been used to produce a structure which has ceramic-like hardness without compensating the toughness significantly. The behaviour of high carbon low-alloy steel as the starting material under different stages of deformation has been studied to differentiate various deformation paths and microstructural transformation processes. Microscopy investigation by secondary electron microscopy, high-resolution electron backscattered diffraction (HR-EBSD) analysis and Transmission electron microscopy (TEM) showed that the key point to achieve ~75% increased hardness in this steel is through generation of nano-structured martensite of less than 50 nm grains size which can be formed due to high impact force. In this paper, we reveal a nano grained steel structure with excellent mechanical properties resulting from phase transformation, uniform dislocation distribution, grain refinement and recrystallization.
Publisher: Elsevier BV
Date: 02-2019
Publisher: MDPI AG
Date: 02-01-2020
DOI: 10.3390/PR8010053
Abstract: Unprecedented advances and innovation in technology and short lifespans of electronic devices have resulted in the generation of a considerable amount of electronic waste (e-waste). Polymeric components present in electronic waste contain a wide range of organic materials encompassing a significant portion of carbon (C). This source of carbon can be employed as a reducing agent in the reduction of oxides from another waste stream, i.e., steelmaking slag, which contains ≈20 wt%–40 wt% iron oxide. This waste slag is produced on a very large scale by the steel industry due to the nature of the process. In this research, the polymeric residue leftover from waste printed circuit boards (PCBs) after a physical-chemical recycling process was used as the source of carbon in the reduction of iron oxide from electric arc furnace (EAF) slag. Prior to the recycling tests, the polymer content of e-waste was characterized in terms of composition, morphology, thermal behavior, molecular structure, hazardous elements such as Br, the volatile portion, and the fixed carbon content. After the optimization of the ratio between the waste slag (Fe source) and the waste polymer (the carbon source), the microstructure of the recycled alloy showed no Br, Cl, S, or other contamination. Hence, two problematic and complex waste streams were successfully converted to a clean alloy with 4 wt% C, 4% Cr, 2% Si, 1% Mn, and 89% Fe.
Publisher: Springer Science and Business Media LLC
Date: 26-07-2019
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.ENVRES.2022.114113
Abstract: Various articles have been written about MOFs, which are organic-inorganic polymer structures that are unique in three-dimensional porosity, crystalline structure, and their ability to adsorb cadmium ion pollutants from aqueous solutions. These materials possess active metal sites, highly porous structures, high specific surfaces, high chemical functionality, and porous topologies. It is necessary to study adsorption kinetics, isotherms, and mechanisms in order to better understand the adsorption process. Adsorption kinetics can provide information about the adsorption rate and reaction pathway of adsorbents. Adsorption isotherms analyze the possibility of absorbances based on the Gibbs equation and thermodynamic theories. Moreover, in practical applications, knowledge of the adsorption mechanism is essential for predicting adsorption reactions and designing MOFs structures. In this review, the latest suggested adsorption mechanisms, kinetics, and isotherms of MOFs-based materials for removing cadmium ions are presented. A comparison is then conducted between different MOFs and the mechanisms of cadmium ion removal. We also discuss the future role of MOFs in removing environmental contaminants. Lastly, we discuss the gap in research and limitations of MOFs as adsorbents in actual applications, and probable technology development for the development of cost-efficient and sustainable MOFs for metal ion removal.
Publisher: Springer Science and Business Media LLC
Date: 22-07-2022
Publisher: Springer Science and Business Media LLC
Date: 11-10-2016
DOI: 10.1038/SREP34958
Abstract: Although high carbon martensitic steels are well known for their industrial utility in high abrasion and extreme operating environments, due to their hardness and strength, the compressive stability of their retained austenite, and the implications for the steels’ performance and potential uses, is not well understood. This article describes the first investigation at both the macro and nano scale of the compressive stability of retained austenite in high carbon martensitic steel. Using a combination of standard compression testing, X-ray diffraction, optical microstructure, electron backscattering diffraction imaging, electron probe micro-analysis, nano-indentation and micro-indentation measurements, we determined the mechanical stability of retained austenite and martensite in high carbon steel under compressive stress and identified the phase transformation mechanism, from the macro to the nano level. We found at the early stage of plastic deformation hexagonal close-packed (HCP) martensite formation dominates, while higher compression loads trigger body-centred tetragonal (BCT) martensite formation. The combination of this phase transformation and strain hardening led to an increase in the hardness of high carbon steel of around 30%. This comprehensive characterisation of stress induced phase transformation could enable the precise control of the microstructures of high carbon martensitic steels, and hence their properties.
Publisher: MDPI AG
Date: 06-08-2018
DOI: 10.3390/JCS2030048
Abstract: After development of world-first marine bio-composite from 100% waste materials, the necessity of obtaining a simulation tool to predict the performance of this novel material under different conditions has arisen. This study examines the combination of empirical optimization and finite element simulation method as an economic and time-effective tool to predict the mechanical performance of novel complex bio-composite mixtures at the design phase. Bio-composite panels were manufactured introducing marine bio-fillers as secondary reinforcements in a wood–polypropylene particulate blend, from 100% waste resources. The particulate panels were subject to tensile test for mechanical characterization. Based on these results, some of the necessary parameters for finite element simulation has defined empirically and a finite element model was developed utilizing ANSYS software, performing a simulation series. Post-processing of the simulation results was carried out to predict the deformation behavior of the material during the three-point bending test. To validate this technique of material definition, the simulated static bending test results were verified with factual physical tests, and both techniques were well in accordance with each other. This simulation method demonstrated reliable feedback on the behavior of materials for the development of innovative complex materials. Therefore, the time invested, materials used and experimental procedures can be significantly reduced, having significant economic benefits for research and industrial projects.
Publisher: Trans Tech Publications Ltd.
Date: 15-10-2006
Publisher: Springer Science and Business Media LLC
Date: 03-2021
Publisher: Springer Science and Business Media LLC
Date: 30-10-2019
DOI: 10.1038/S41598-019-52228-Z
Abstract: It is commonly known that precipitation of secondary phase in non-ferrous alloys will affect the mechanical properties of them. But due to the nature of dual-phase low-alloy high-carbon steel and its high potential of precipitation of cementite, there is limited study on tailoring the mechanical and corrosion properties of this grade of steel by controlling the precipitation of different phases. Predicting and controlling precipitation behaviour on this grade of steel is of great importance towards producing more advanced applications using this low-cost alloy. In this study the new concept of selective-precipitation process for controlling the mechanical and corrosion behaviour of dual-phase low-alloy high-carbon steel has been introduced. We have investigated the precipitation of different phases using in-situ observation ultra-high temperature confocal scanning laser microscopy, image analyser – ImageJ, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and electron probe microanalysis (EPMA). Volume fraction of each phase including retained austenite, martensite and precipitated phases was determined by X-ray diffraction (XRD), electrochemical corrosion test by Tafel extrapolation method and hardness performance by nanoindentation hardness measurement. The experimental results demonstrated that, by controlling the precipitations inside the matrix and at grain boundaries through heat treatment, we can increase the hardness of steel from 7.81 GPa to 11.4 GPa. Also, corrosion resistance of steel at different condition has been investigated. This new approach will open new possibility of using this low-cost steel for high performance applications.
Publisher: Elsevier BV
Date: 2021
Publisher: MDPI AG
Date: 12-10-2018
DOI: 10.3390/MA11101964
Abstract: The abundant application of metallized paper and the quick growth of their wastes lead to the removal of a huge amount of valuable resources from economic cycle. In this work, for the first-time, the thermal micronizing technique has been used to directly transform the metallized paper wastes to Al-Si nano-rod and Al nano-particles for use as the input in different manufacturing sectors such as additive manufacturing or composite fabrication. Structure of metallized paper has been investigated using FT-IR analysis and first-principle plane-wave calculation. Then, based on the structure of metallized paper, thermal micronizing technique has been modified to directly transform this waste into nano materials. Structure of nano-particles and nano-rods has been investigated using SEM, TEM, and XPS analysis. Results showed two main Al-Si nano-rod and Al nano-particle morphologies created as a result of the different surface tensions, which facilitate their separation by Eddy current separation technique. These quick transformation and facile separation together make this technique a unique process to deal with this complex waste and producing value-added products which can re-capture these high value materials from waste and make the reforming economically viable.
Publisher: MDPI AG
Date: 21-03-2018
DOI: 10.3390/MET8040199
Abstract: Industrial application of high carbon low alloy steel with the dual-phase structure of martensite and austenite has increased drastically in recent years. Due to its excellent compression strength and its high abrasion resistance, this grade of steel has used as a high performance cutting tool and in press machinery applications. By increasing the usage of more corrosive media in industrial practice and increasing the demand for reducing the production cost, it is crucial to understand the effect of the small addition of Cr on the corrosion behaviour of this grade of steel. In this study, this effect was investigated using Secondary Electron Microscopy (SEM) and in-situ Atomic Force Microscopy (AFM) in the sodium chloride solution. Also, the corrosion rate was measured using the Tafel polarisation curve. It has been found that the small addition of Cr increased the stability of retained austenite, thus improving its corrosion resistance and reducing its corrosion rate. This effect has been acquired through in-situ high resolution topography images in which the s les were submerged in a corrosive solution. It has been demonstrated that the corrosion rate was reduced when the stability of austenite enhanced.
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1GC00354B
Abstract: Cu-based heterojunction ultrathin layered films, fabricated from e-waste, showed a dual-functionality for energy storage and energy harvesting applications. LCA of this e-waste valorisation highlighted the importance of such value-added recycling.
Publisher: MDPI AG
Date: 04-09-2019
Abstract: Corrosion resistance of steel has attracted substantial interest for manufacturing applications to reduce costs corresponding to part failures, unexpected maintenance, and shortening lifespan. Meanwhile, millions of tonnes of slag, non-recyclable glass, and automotive shredder residue (ASR) are discarded into landfills every year, polluting the environment. Combining these two major issues, we delivered an alternative solution to enhance corrosion resistance of high-C steel. In this research, utilisation of these wastes (which were chemically bonded into steel substrate) as sources for production of multi-hybrid layering—including the multi-phase ceramic layer, the carbide layer, and the selective diffusion layer—was successfully achieved by single step surface modification technology. High-resolution topographical imaging by SEM and chemical composition analysis in micron-volume by electron probe micro analyser (EPMA) were performed. Nano-characterisation by atomic force microscopy (AFM) using the PeakForce quantitative nanomechanical mapping (PF-QNM) method was conducted to define Young’s modulus value of each phase in detail. Results revealed improvement of corrosion resistance by 39% and a significantly increased hardness of 13.58 GPa. This integrated approach is prominent for economic and environmental sustainability, consolidating industry demands for more profits, producing durable, steel components in a cost effective way to reduce dependency on new resources, and minimising negative impacts to the environment from disposal of wastes to the landfills.
Publisher: MDPI AG
Date: 03-01-2023
DOI: 10.3390/JCS7010008
Abstract: Carbon-based materials have become an indispensable component in a myriad of domestic and industrial applications. Most of the carbon-based end-of-life products discussed in this review end up in landfills. Where recycling is available, it usually involves the production of lower-value products. The allotropic nature of carbon has been analysed to identify novel materials that could be obtained from used products, which also transform into a secondary carbon resource. Thermal transformation of carbon-rich wastes is a promising and viable pathway for adding value to waste that would otherwise go to landfills. The valorisation routes of four different carbon-rich wastes by thermal transformation are reviewed in the study—automotive shredder residue (ASR), textile wastes, leather wastes, and spent coffee grounds (SCGs). Textile wastes were thermally transformed into carbon fibres and activated carbon, while ASRs were used as a reductant to produce silicon carbide (SiC) from waste glass. The leather wastes and spent coffee grounds (SCGs) were employed as reductants in the reduction of hematite. This paper examines the possible routes of thermally transforming carbon-rich wastes into different industrial processes and applications. The transformation products were characterised using several techniques to assess their suitability for their respective applications. The strategy of valorising the wastes by thermal transformation has successfully prevented those wastes from ending up in landfills.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 12-2020
Publisher: Maney Publishing
Date: 03-2004
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 2017
Publisher: MDPI AG
Date: 29-07-2023
Abstract: Generally, fossil carbon materials (coal, coke/char, and petroleum coke), biological carbon materials (charcoal, woodchips), and quartz from the earth’s crust are sources of carbon and silica to synthesise silicon carbide (SiC) at temperatures between 2000 and 2200 °C. The study investigated the isothermal and non-isothermal kinetics of synthesising SiC from automotive shredder residues (ASR) and windshield glass of end-of-life-vehicle (ELVs) at 1300 °C, 1400 °C, and 1500 °C for 30 min. The kinetics of ASR and waste glass degradation were studied by relating the thermogravimetric data via the Coats–Redfern model. The reaction mechanism includes the rapid formation of a gaseous SiO intermediate, and carbon reduction of the SiO to SiC is reaction-rate-controlling. The understanding of kinetics inferred that the optimisation of SiC formation is entirely associated with the conversion of SiO2 to SiO vapour and their reaction with CO and carbon particles. The kinetic parameters of the degradation of mixed ASR and waste glass were determined, and the activation energy of mixed ASR and glass for non-isothermal conditions are 22.48 kJ mol−1, 2.97 kJ mol−1, and 6.5 kJ mol−1, and for the isothermal study to produce SiC is 225.9 kJ mol−1, respectively. The results confirmed that this facile way of synthesising SiC would conserve about 50% of chemical energy compared to the traditional way of producing SiC. A beneficial route of transforming the heterogenous ASR and glass wastes into SiC with economic and environmental benefits is recognised.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Springer International Publishing
Date: 2018
Publisher: Springer Science and Business Media LLC
Date: 07-01-2019
Publisher: Springer Science and Business Media LLC
Date: 12-07-2019
DOI: 10.1038/S41598-019-46450-Y
Abstract: Manganese sulphide (MnS) is one of the major non-metallic inclusions in steel with huge impact on steel property. In the case of high carbon steel, due to higher sulphur content and its brittleness, controlling MnS formation is one of the main issues. MnS has a complicated precipitation mechanism during solidification in liquid and solid steel and at the interface with oxide inclusions. Higher sulphur content, lower melting point and different oxide inclusions in high carbon steel will cause MnS precipitation at different stages. In this study, different stages of MnS precipitation from liquid and/or solid in high carbon steel and at the interface with oxide inclusion were investigated comprehensively via two different types of High Temperature Confocal Scanning Laser Microscope (HTCSLM). S les were analysed further using SEM-EDS for better understanding the pertaining mechanisms. MnS precipitation on the surface of liquid steel was observed in situ in a HTCSLM by the use of a concentric solidification technique. Additionally, formation of MnS following solidification and at the interfaces of oxide inclusions, was investigated in situ in a HTCSLM, which has a uniform temperature profile across the specimen. These comprehensive descriptions about different stages of MnS precipitation in high carbon steel have been conducted for the first time and provide crucial information for controlling MnS morphology in high carbon steel.
Publisher: Springer Science and Business Media LLC
Date: 08-12-2016
DOI: 10.1038/SREP38740
Abstract: Abrasion and corrosion resistant steel has attracted considerable interest for industrial application as a means of minimising the costs associated with product/component failures and/or short replacement cycles. These classes of steels contain alloying elements that increase their resistance to abrasion and corrosion. Their benefits, however, currently come at a potentially prohibitive cost such high performance steel products are both more technically challenging and more expensive to produce. Although these methods have proven effective in improving the performance of more expensive, high-grade steel components, they are not economically viable for relatively low cost steel products. New options are needed. In this study, a complex industrial waste stream has been transformed in situ via precisely controlled high temperature reactions to produce an ultrahard ceramic surface on steel. This innovative ultrahard ceramic surface increases both the hardness and compressive strength of the steel. Furthermore, by modifying the composition of the waste input and the processing parameters, the ceramic surface can be effectively customised to match the intended application of the steel. This economical new approach marries industry demands for more cost-effective, durable steel products with global imperatives to address resource depletion and environmental degradation through the recovery of resources from waste.
Publisher: Elsevier BV
Date: 2019
Publisher: Springer Science and Business Media LLC
Date: 07-10-2020
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.WASMAN.2016.02.003
Abstract: Large increasing production volumes of automotive shredder residue (ASR) and its hazardous content have raised concerns worldwide. ASR has a desirable calorific value, making its pyrolysis a possible, environmentally friendly and economically viable solution. The present work focuses on the pyrolysis of ASR at temperatures between 950 and 1550°C. Despite the high temperatures, the energy consumption can be minimized as the decomposition of ASR can be completed within a short time. In this study, the composition of ASR was investigated. ASR was found to contain about 3% Ti and plastics of high calorific value such as polypropylene, polyethylene, polycarbonate and polyurethane. Based on thermogravimetric analysis (TGA) of ASR, the non-isothermal degradation kinetic parameters were determined using Coats-Redfern's and Freeman and Carroll methods. The evolved gas analysis indicated that the CH4 was consumed by the reduction of some oxides in ASR. The reduction reactions and the presence of Ti, silicates, C and N in ASR at 1550°C favor the formation of specific ceramics such as TiN and SiC. The presence of nano-ceramics along with a highly-crystalline graphitic carbon in the pyrolysis residues obtained at 1550°C was confirmed by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Raman imaging microscope (RIM) analyses.
Publisher: MDPI AG
Date: 28-11-2018
DOI: 10.3390/MA11122404
Abstract: Steel has played a primary role as structural and fabricating materials in various industrial applications—including the construction sector. One of the most important properties of steel that required a constant improvement is corrosion resistance specifically in corrosive environment. For this purpose, various approaches have been conducted through different heat treatment parameters to compare its microstructural engineering on chemical and mechanical properties. In this paper, correlation of different microstructure on corrosion resistance and hardness properties have been investigated. Three different heat treatment cycle have been applied on carbon steel with same composition to prepare dual-structure (DS) steel that consisted of ferrite earlite and triple-structure (TS) with ferrite earlite/bainite and ferrite/bainite/martensite. Phase transformation during heat treatment process was analyzed through in-situ ultra-high temperature confocal microscopy. Effect of corrosion behavior on these steels was investigated by Tafel plot, Scanning Electron Microscopy (SEM), 3D laser scanning confocal microscopy (3DLSCM), and calculation of phase volume fraction by ImageJ. Mechanical test was conducted by Vickers hardness test. It has been found that TS steels that have improvement in corrosion resistance accounted around 5.31% and hardness value for up to 27.34% more than DS steel, because of tertiary phase—bainite/martensite. This corrosion rate was reduced due to decreased numbers of pit growth and lower level of boundary corrosion as bainite/martensite phases emerged.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2021
Publisher: American Chemical Society (ACS)
Date: 02-05-2019
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 09-2018
Publisher: Springer Science and Business Media LLC
Date: 20-06-2019
Publisher: Springer Science and Business Media LLC
Date: 07-02-2019
DOI: 10.1038/S41598-018-38120-2
Abstract: When corrosion is the dominant failure factor in industrial application and at the same time high mechanical properties are required, aluminum bronze is one of the best candidates. Hence, there is a continuous quest for increasing the lifetime of aluminum bronze alloys through enhancing the abrasion and corrosion resistance. Existing methods are based on modifying the bulk properties of alloy or surface modification which required sophisticated equipment and process control. This approach has limited application for advanced components because of high price and difficulty to apply. In this research, we developed an innovative approach to enhance the corrosion and abrasion resistance of aluminum bronze through selective surface diffusion process. In this process, we have used waste materials as input and the modified surface has formed in a single and green process. New surface structure consists of finely dispersed kappa phase (χ ) in uniform alpha (α) solid solution matrix. Results have demonstrated that this uniform diffused modified surface layer has improved hardness of the base material and both corrosion and abrasion resistance has increased. This novel surface modification technique has opened a pathway for using waste materials as input for surface modification of aluminum bronze to meet the needs of industrial applications in a cost effective and environmentally friendly way.
Publisher: WIT Press
Date: 26-06-2006
DOI: 10.2495/HT060251
Publisher: Springer Science and Business Media LLC
Date: 06-09-2016
Publisher: Elsevier BV
Date: 08-2020
Publisher: Trans Tech Publications, Ltd.
Date: 07-2008
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.141-143.463
Abstract: The needs for high-strength and light weight structural materials have increased in automotive and aerospace structure applications. The semi-solid processed light alloys inherently offer the opportunity to produce high integrity components for these requirements. Various processing methods exist for applying agitation to a molten metal during solidification to obtain metal slurries suitable for semi-solid metal processing. In this paper, a new technique (Cup-Cast method) to achieve semi-solid metal structure using agitation and direct spherical growth during solidification is reported. Cup-Cast method is the most quick and simple semi-solid processing route which semi-solid slurry would be prepared just by pouring molten metal into a metallic cup. In this study Cup-Cast method was introduced and effect of process parameters on micro-structural characterization of slurry prepared by this method was investigated.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Springer Science and Business Media LLC
Date: 02-06-2020
Publisher: Iron and Steel Institute of Japan
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 29-06-2021
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.JHAZMAT.2019.03.013
Abstract: Electronic waste (e-waste) has become an urgent issue in digitally dependent world, owing to the unprecedented use of electronic devices and this has compelled the world to develop new techniques to recycle such wastes. In this work, one of problematic and high volume global waste stream, i.e., end-of-life printed circuit boards (PCBs), was examined for recycling. Using ion-exchange (adsorption/desorption) technique, heavy metals (Cu, Zn, Ni, and Pb), and Al were selectively recovered and separated. Three macroporous ion-exchange resins (Amberlite IRA 743, Lewatit TP 208, and Lewatit TP 260) were applied to extract, isolate and concentrate the heavy metals. The process factors (resin load, solution temperature and contact time) were investigated and kinetic behavior of adsorption was studied using three different models. Based on the process factors, the functionality and selectivity of the ion-exchange resins were discussed. A negligible amount of Ni and Zn adsorption on the surface of resin 743 indicates its high selectivity. This study also proves that selective isolation of hazardous elements such as Pb can be performed under specified sorption parameters. Also, the distribution of adsorbed cations throughout the resin beads was studied via elemental analysis. The distribution of Cu as the main element was not homogenous that signifies the higher practical capacity of the ion-exchanger. Finally, a stripping step was applied to modify the working media and to examine the reversibility and selectivity of the desorption process.
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer London
Date: 30-09-2014
Publisher: MDPI AG
Date: 26-07-2018
DOI: 10.3390/MET8080580
Abstract: Understanding the effect of high strain rate deformation on microstructure and mechanical property of metal is important for addressing its performance as high strength material. Strongly motivated by the vast industrial application potential of metals having excellent hardness, we explored the phase stability, microstructure and mechanical performance of an industrial grade high carbon steel under different compressive strain rates. Although low alloyed high carbon steel is well known for their high hardness, unfortunately, their deformation behavior, performance and microstructural evolution under different compressive strain rates are not well understood. For the first time, our investigation revealed that different strain rates transform the metastable austenite into martensite at different volume, simultaneously activate multiple micromechanisms, i.e., dislocation defects, nanotwining, etc. that enhanced the phase stability and refined the microstructure, which is the key for the observed leap in hardness. The combination of phase transformation, grain refinement, increased dislocation density, formation of nanotwin and strain hardening led to an increase in the hardness of high carbon steel.
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.JENVMAN.2017.05.028
Abstract: This study investigates, verifies and determines the optimal parameters for the selective thermal transformation of problematic electronic waste (e-waste) to produce value-added copper-tin (Cu-Sn) based alloys thereby demonstrating a novel new pathway for the cost-effective recovery of resources from one of the world's fastest growing and most challenging waste streams. Using outdated computer printed circuit boards (PCBs), a ubiquitous component of e-waste, we investigated transformations across a range of temperatures and time frames. Results indicate a two-step heat treatment process, using a low temperature step followed by a high temperature step, can be used to produce and separate off, first, a lead (Pb) based alloy and, subsequently, a Cu-Sn based alloy. We also found a single-step heat treatment process at a moderate temperature of 900 °C can be used to directly transform old PCBs to produce a Cu-Sn based alloy, while capturing the Pb and antimony (Sb) as alloying elements to prevent the emission of these low melting point elements. These results demonstrate old computer PCBs, large volumes of which are already within global waste stockpiles, can be considered a potential source of value-added metal alloys, opening up a new opportunity for utilizing e-waste to produce metal alloys in local micro-factories.
Publisher: Elsevier BV
Date: 09-2018
Publisher: Trans Tech Publications Ltd.
Date: 07-07-2008
Publisher: MDPI AG
Date: 16-08-2019
DOI: 10.3390/MET9080902
Abstract: Series of super-hard ceramic layers have been successfully developed on high carbon steels, with a significant improvement of corrosion resistance and hardness, without changing the original properties, which were derived from mixtures of slag (electric arc furnace), waste glass (bottles), and automotive shredder residue (ASR) plastics (polypropylene) via the single step surface modification technique. Microstructural analysis by laser scanning confocal microscopy (LSCM), crystallography analysis by X-ray diffraction (XRD), micro-level chemical analysis by scanning electron microscopy and energy dispersive spectroscopy (SEM and EDS), and depth profile surface analysis with three-dimensional chemical mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS), followed by electrochemical corrosion test by the Tafel method and hardness test—Vickers hardness measurement. Three areas have been classified, modified surface, interface, and main substrate areas as the synthesis of ceramic layers into surface of the steels that thermodynamically formed during the heat treatment process. Chemical composition analyses have revealed that generated layers consisting of chromium (Cr)- and magnesium (Mg)-based compound have shown an improved corrosion resistance to 52% and hardness to 70% without modifying the initial volume fraction of constituent phases–martensite and retained austenite. These findings have substantially highlighted to the potential use of waste-integrated inputs as raw materials for production in cost-effective way, concurrently decreasing the demand on new resource for coating, alleviating the disadvantageous impact to the environment from waste disposal in landfills.
Publisher: Elsevier BV
Date: 06-2019
Publisher: Emerald Publishing Limited
Date: 30-08-2018
Publisher: MDPI AG
Date: 05-08-2022
DOI: 10.3390/JCS6080230
Abstract: Plastic has transformed the world however, it generates a huge amount of waste plastics. It is well evident that, if urgent action is not undertaken on plastic pollution, it will pose threats to not only the environment, but also human life. Just simply discarding waste plastics will result in wasting a lot of valuable materials that could be recycled. Recently, the use of waste plastics has been considered for producing wood plastic composites (WPCs), which are superior to normal wood. Waste plastics are pelletized using an extruder and are then subjected to injection molding. In this study, investigations were carried out to determine the possibility of producing WPCs without the palletization of waste plastic to turn WPC production into a shorter, simple, and easy-to-achieve process. Here, a waste milk bottle, a familiar single-use plastic, was picked as a case study. Waste plastic granules and wood particles were mixed and directly injection molded to produce valuable WPCs. The water absorption of WPCs with 20% wood is 0.35%, and this increased to 0.37% when wood content was increased to 40%. The tensile strength at yield, elongation at break, and impact strength of WPCs with 20% wood content are 19.54 MPa, 5.21%, and 33.92 KJ/m2, respectively, whereas it was 17.23 MPa, 4.05%, and 26.61 KJ/m2 for the WPCs with 40% wood content. This process can be a potential solution for two problematic wastes at the same time.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 12-1970
Publisher: Elsevier BV
Date: 2017
Publisher: Japan Institute of Metals
Date: 2007
Publisher: Elsevier BV
Date: 03-2021
Publisher: Trans Tech Publications, Ltd.
Date: 10-2006
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.116-117.569
Abstract: Cup-cast method is a new method deals with semi-solid slurry preparation recently developed by the authors. In this method, suspension of globular solid particles in molten metal is prepared by controlling the nucleation and growth of solid-particles through the simplest and quickest techniques. In this method, heat transfer phenomenon plays an important role in governing the shape, size, and fraction of solid particles. In the current study, a heat transfer model was proposed and applied to Al-A356 alloy semi-solid slurry preparation. The heat transfer model was based on heat balance consideration between cup and slurry and it was in a good agreement with experimental results.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/S41598-017-13749-7
Abstract: This study identifies for the first time, the hybrid structure of the white layer in high carbon steel and describes its formation mechanism and properties. The so-called ‘white layer’ in steel forms during high strain rate deformation and appears featureless under optical microscopy. While many researchers have investigated the formation of the white layer, there has been no definitive study, nor is there sufficient evidence to fully explain the formation, structure and properties of the layer. In this study, the formation, morphology and mechanical properties of the white layer was determined following impact testing, using a combination of optical and SE- microscopy, HR-EBSD, TKD and TEM as well as nano-indentation hardness measurements and FE modelling. The phase transformation and recrystallization within and near the white layer was also investigated. The microstructure of the steel in the white layer consisted of nano-sized grains of martensite. A very thin layer of austenite with nano sized grains was identified within the white layer by HR-EBSD techniques, the presence of which is attributed to a thermally-induced reverse phase transformation. Overall, the combination of phase transformations, strain hardening and grain refinement led to a hybrid structure and an increase in hardness of the white layer.
Publisher: MDPI AG
Date: 24-11-2017
DOI: 10.3390/JMMP1020021
Publisher: Springer Science and Business Media LLC
Date: 22-06-2019
DOI: 10.1007/S11356-019-05596-Y
Abstract: Despite attempts to enhance the recycling of waste printed circuit boards (WPCBs), the simultaneous recovery of major metals of WPCBs using an efficient approach is still a great challenge. This study mainly concerned with applying an effective statistical tool to optimize the recovery of metal content (i.e., Cu, Fe, Zn, Pb, Ni, Sn, and Al) embedded in WPCBs using a leaching agent without any additive or oxidative agent. Another target was to optimize a multi-response recovery process by minimizing time, energy, and acid consumption during the leaching. Effective parameters and their levels, including leaching time (20-60 min), temperature (25-45 °C), solid to liquid (S/L) ratio (1/8-1/20 g/ml), and acid molarity (1-2.7 M), were optimized. A well-established statistical approach (i.e., response surface methodology (RSM)) was applied to precisely quantify and interpret the effects. General optimum conditions for nine responses were introduced with the desirability of ≈ 85%. Finally, the solid residue of leaching was characterized and results showed the morphology, structure, and composition of the residue content (i.e., polymers and ceramics) remained the same after the leaching, indicating the neutral behavior of the leaching process on these two materials. Also, thermal behavior and phase analysis of the original WPCBs and leaching residue were compared and analyzed. Graphical abstract.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 07-2019
Publisher: MDPI AG
Date: 22-01-2018
DOI: 10.3390/MET8010078
Abstract: In recent years, the research regarding waste conversion to resources technology has attracted growing attention with the continued increase of waste accumulation issues and rapid depletion of natural resources. However, the study, with respect to utilizing plastics waste as carbon resources in the metals industry, is still limited. In this work, an environmentally friendly approach to utilize snack packaging plastic waste as a valuable carbon resources for steel carburization is investigated. At high temperature, plastic waste could be subject to pyrolytic gasification and decompose into small molecular hydrocarbon gaseous products which have the potential to be used as carburization agents for steel. When heating some snack packaging plastic waste and a steel s le together at the carburization temperature, a considerable amount of carbon-rich reducing gases, like methane, could be liberated from the plastic waste and absorbed by the steel s le as a carbon precursor for carburization. The resulting carburization effect on steel was investigated by optical microscopy, scanning electron microscopy, electron probe microanalyzer, and X-ray photoelectron spectrometer techniques. These investigation results all showed that snack packaging plastic waste could work effectively as a valuable carbon resource for steel carburization leading to a significant increase of surface carbon content and the corresponding microstructure evolution in steel.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 2016
Start Date: 06-2015
End Date: 07-2020
Amount: $2,181,756.00
Funder: Australian Research Council
View Funded ActivityStart Date: 01-2021
End Date: 01-2026
Amount: $3,317,500.00
Funder: Australian Research Council
View Funded Activity