Materials For Engineering Applications Research Articles

Weak ferromagnetism linked to the high-temperature spiral phase of YBaCuFeO5

The layered perovskite ${\mathrm{YBaCuFeO}}_{5}$ is a rare example of a cycloidal spiral magnet whose ordering temperature ${T}_{\text{spiral}}$ can be tuned far beyond room temperature by adjusting the degree of ${\mathrm{Cu}}^{2+}/{\mathrm{Fe}}^{3+}$ chemical disorder in the structure. This unusual property qualifies this material as one of the most promising spin-driven multiferroic candidates. However, very little is known about the response of the spiral to magnetic fields, crucial for magnetoelectric cross-control applications. Using bulk magnetization and neutron powder diffraction measurements under magnetic fields up to 9 T, we report here a temperature-magnetic field phase diagram of this material. Besides revealing a strong stability of the spiral state, our data uncover the presence of weak ferromagnetism coexisting with the spiral modulation. Since ferromagnets can be easily manipulated with magnetic fields, this observation opens new perspectives for the control of the spiral orientation, directly linked to the polarization direction, as well as for a possible future use of this material in technological applications.

A Phase-Field Perspective on Mereotopology

Mereotopology is a concept rooted in analytical philosophy. The phase-field concept is based on mathematical physics and finds applications in materials engineering. The two concepts seem to be disjoint at a first glance. While mereotopology qualitatively describes static relations between things, such as x isConnected y (topology) or x isPartOf y (mereology) by first order logic and Boolean algebra, the phase-field concept describes the geometric shape of things and its dynamic evolution by drawing on a scalar field. The geometric shape of any thing is defined by its boundaries to one or more neighboring things. The notion and description of boundaries thus provides a bridge between mereotopology and the phase-field concept. The present article aims to relate phase-field expressions describing boundaries and especially triple junctions to their Boolean counterparts in mereotopology and contact algebra. An introductory overview on mereotopology is followed by an introduction to the phase-field concept already indicating its first relations to mereotopology. Mereotopological axioms and definitions are then discussed in detail from a phase-field perspective. A dedicated section introduces and discusses further notions of the isConnected relation emerging from the phase-field perspective like isSpatiallyConnected, isTemporallyConnected, isPhysicallyConnected, isPathConnected, and wasConnected. Such relations introduce dynamics and thus physics into mereotopology, as transitions from isDisconnected to isPartOf can be described.

Analysis of the Decomposition using the Short Degradation Technique of Polylactic Acid/Halloysite Nanotube Biocomposites

The article presents results on the decomposition of polylactic acid (PLA)/halloysite nanotube (HNT) biocomposites. Experiments were carried out in laboratory conditions simulating composting in the industrial pile using the so-called short degradation method. In this paper, the effects of the composting process (duration from 30 to 90 days) on the behavior of PLA/HNT composites were studied. In addition, the selected physicochemical properties of PLA/HNTs biocomposites such as the average molecular weight were investigated. The results obtained confirmed the viability of composting PLA with halloysite which contributes to the reduction of plastic waste and the use of this material in technological applications.

Functional Material Systems Based on Soft Cages.

Discrete molecular soft cages integrate multiple functionalities in one molecule. They express their functions from the confined space in their cavity, functional groups in the cavity interior wall and exterior wall, and the chelating nodes in many chelating cages. Such functional integrity render cage molecules special applications in material engineering. Increasing applications of cage molecules in material design have been reported in recent years. Compared with other cavity-rich molecular structures such as metal-organic framework (MOF) or covalent organic frameworks (COF), discrete soft cages present the unique advantage of material design flexibility, that they can easily composite with nanoparticles or polymers and exist in materials of various forms. We document the development of cage-based materials in recent years and expect to further inspire materials engineering to integrate contribution from the functionality specificity of cage molecules and ultimately promote the development of functional materials and thus human life qualities.

Editorial

This special issue of University of Porto Journal of Engineering contains selected papers presented at the 3rd International Conference on Materials Design and Applications 2020 (MDA 2020), held in online during 5-6 November 2020. The goal of the conference was to provide a unique opportunity to exchange information, present the latest results as well as to discuss issues relevant to materials design and applications. The focus is on fundamental research and application areas in the field of the design and application of engineering materials, predominantly within the context of mechanical engineering applications. This includes a wide range of materials engineering and technology, including metals, e.g., lightweight metallic materials, polymers, composites, and ceramics. Advanced applications include manufacturing of new materials, testing methods, multi-scale experimental and computational aspects. Approximately 155 papers were presented by researchers from nearly 30 countries.
 In order to disseminate the work presented in MDA 2020, selected papers were prepared which resulted in the present special issue. A wide range of topics are covered resulting in 10 papers dealing with metals (first three papers), composites (three papers), tribology (one paper) and machining (three papers). The papers presented here are good examples of the latest trends related materials design and applications.
 The organizer and editor wish to thank all the authors for their participation and cooperation, which made this volume possible. Finally, I would like to thank the team of University of Porto, especially Dr. Luís Miguel Costa, for the excellent cooperation during the preparation of this volume.

Analysis of wear properties and surface roughness of laser additive manufactured (LAM) Ti and TiB2 metal matrix composite

Abstract Industrial revolution in engineering materials applications through additive manufacturing has influenced the steel application in engineering industry. Limitations of wear of carbon steel has called for research focus in improving steel quality in wear resistance. Metallurgical applications of heat treatment were less effective as issues of temperature control; grain boundaries were evident. Matrix composite materials of better mechanical properties have been made use of to complement existing steel. This research focuses on the use of titanium, and titanium boride composite through laser cladding of addictive manufacturing. The admix composites were ‘mixed at different mass ratio, laser power and scan rate. A computer aided design (CAD) of design expert 9 was used to design the optimized parameters for the experimental analysis. Thirteen runs of random parameters of varying laser power and scanning speed were executed. An optimized laser power of 1500 W and scan rate of 1.2 m/min were derived and utilized. Nanocomposites of Titanium and Titanium di boride was at ratio loaded and cladded on steel rail surface. Metallurgical characterization of microscopic and macroscopic view was carried out. Different microstructural evolution was studied and analyzed. The wear tests were carried out at different loads of 2 N, 5 N and 10 N, respectively. The wear volume and wear rate were calculated. The least wear rate and wear volume was at the 50/50 mix ratio. A correlation and relationship between the wear properties, surface roughness and composition were examined.

‘Synthesis and properties of amorphous nanosilica from rice husk and its composites

Amorphous nanosilica (SiO2) was prepared from rice husk by a cost-effective and environment-friendly method. Magnetic nanocomposite has been prepared by using injection molding equipment from amorphous nanosilica, ferrites, and PVDF. The XRD pattern analysis reveals the amorphous nature of the silica. The particle size of SiO2 was observed from the SEM and TEM analysis and found to be very small, which suggests the formation of amorphous nanosilica from the rice husk. FTIR spectra show the absorption peaks of SiOiSi (silanol) functional group. The photoluminescence spectrum reveals the broad excitation of radiation in the visible region. A characteristics peak in UV–Vis absorption spectra occurs at 365 nm, and the optical band gap was found to be 3.35 eV. Magnetic study shows the diamagnetic nature of amorphous nanosilica. The nanocomposite of amorphous nano silica-Ferrite-PVDF exhibits ferromagnetic nature due to the presence of ferrite in the nanocomposite. The magnetic hysteresis loop of nanocomposite reveals that the materials can be used as polymer magnet. The physical properties of amorphous nansilica and its composite with PVDF and ferrite have been explored in the present article. The present study may help to use prepared nanosilica materials in technological applications.

A novel study on time-dependent viscosity model of magneto-hybrid nanofluid flow over a permeable cone: applications in material engineering

The dominating features of hybrid nanofluid such as high heat transfer rates, excellent electrical and thermal conductivity, and low cost, have been successfully attracted the attention of global researchers. In light of these amazing features, the current mathematical research explores the effects of variable viscosity on radiative magneto-hybrid nanofluid (Cu–Fe $$_{3}$$ O $$_{4}$$ /water) flow over a vertical cone inside porous medium. In addition, variable heat flux relation with boundary layer flow in the presence of heat generation/absorption is scrutinized. The Crank–Nicolson scheme together with Thomas algorithm is implemented to obtain the numerical solutions of constructed mathematical model with the aid of MATLAB software. The impact of various controlling parameters on virtual flow properties, temperature and velocity is scrutinized, and the obtained outcomes are exhibited graphically. The physically important quantities such as heat transfer coefficient and wall shear stress are evaluated versus governing constraints, and the results are summarized in the tables and illustrated graphically as well. The results unveil that the thermal performance of the system increases in the presence of nanoparticles, magnetic field and thermal radiation. Moreover, velocity of the fluid increases due to high permeability effects. The results of this work may have useful applications in materials science and engineering.

Direct Measurement of Temperature Diffusivity of Nanocellulose-Doped Biodegradable Composite Films.

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of nanocellulose-doped starch–polyurethane nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2 wt%. of nanocellulose were synthesised by a simple chemical process and are biodegradable. Films of a high optical transmittance (for a 200 m thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on (1) a resistance change and (2) micro-thermocouple detected voltage modulation caused by the heat wave, were used for the polymer films with cross sections of ∼100 m thickness. Twice different in-plane and out-of-plane temperature diffusivities were directly determined with high fidelity: m/s and m/s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite biodegradable polymer films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this polymer nanocomposite.

Phase integrity of zinc oxide doped zirconia under low compacting pressure

Abstract The phase stability of zirconia (ZrO2) under external perturbation draws the attention of researchers, as it governs the practical use of this material in technological applications. In this article, the phase transition in zinc oxide (ZnO) doped ZrO2 is addressed by exploiting complementary methodologies, X-ray diffraction, and Raman spectroscopic measurements. We have observed a pressure-induced partial phase transformation in the doped ZrO2 system for a compacting pressure of less than 1 GPa. It is noteworthy that the level of compacting pressure used in this study is much lower than the range of pressure, reported in the literature, for observing phase transition in pure and doped ZrO2 using other high-pressure experiments. To understand the underlying dynamics of low pressure-induced phase transformation, we carried out density functional theory calculations for the doped supercell. We have discussed the local bonding environment around the dopant metal ion (Zn2+ in the present case), which, we believe, leads to the phase evolution in a real system.

Bayesian inference of solid-liquid interfacial properties out of equilibrium.

Solid-liquid interfacial properties out of equilibrium provide the essential information required for understanding and controlling solidification microstructures in metallic materials. However, few studies have attempted to reveal all interfacial properties out of equilibrium in detail. The present study proposes an approach for simultaneously estimating all interfacial properties in a pure metal below the melting point on the basis of the Bayesian inference theory. The solid-liquid interfacial energy, interfacial mobility, and anisotropy parameters in pure Fe are estimated by combining molecular dynamics simulation with phase-field simulation using an ensemble Kalman filter, which is a data assimilation technique. Furthermore, the temperature dependences of all interfacial parameters are computed and discussed. In summary, the proposed multiscale approach integrates atomistic and microstructural simulations within the framework of data science and it has considerable potential for a wide variety of applications in materials engineering.

Karbon Nanotüpler Üzerine Gama Radyasyonu Etkisi

An extensive review of the gamma radiation effect on carbon nanotubes is given in this study. The interaction of carbon nanotubes with different doses and energies gamma radiation has been studied in recent years. Carbon nanotubes are desirable materials in technological applications because of their extra features such as good thermal properties, ultra-light structures, different conductivity properties, durability, and superior heat resistance. For these reasons, they are used extensively in device construction. These devices are used extensively in environments exposed to radiation such as medicine, aviation, nuclear reactors, nuclear waste storage. Knowing the response of carbon nanotube materials to radiation is very important for the stability of the devices made. As can be seen from the literature review, the interaction of the material with gamma radiation is quite variable according to the type of material, the purity, and the atomic lattice of material, dose and energy of the applied radiation and the environment (water, air, etc.) subjected to.

Elastomeric Composites Containing SBR Industrial Scraps Devulcanized by Microwaves: Raw Material, Not a Trash

Environmental concerns about waste management systems have stimulated the search for technological and economical alternatives that introduce waste as raw material for production cycles. In this sense, this study aimed to develop and characterize styrene-butadiene rubber (SBR) composites that contain industrial rubber scraps devulcanized by microwaves (SBR-r) as a reinforcing filler. The scraps were ground under ambient conditions. From the obtained powder (SBR-r), composites were prepared, varying the exposure time of the powder to the microwaves (1, 2, and 3 min), as well as the SBR-r content. These composites were compared to a Reference sample (base formulation without SBR-r). The vulcanization parameters were determined by an oscillating disk rheometer. After vulcanization, the composites were characterized by mechanical properties (tensile and tear strength, and compression set). These properties were also evaluated after accelerated aging in an air oven and a UV chamber (ultraviolet light). The results indicated that as a result of increasing the exposure time of the waste to the microwaves, no significant influence in the composite properties was observed. Aged samples presented higher results as compared with the Reference sample (tensile strength up to 175% higher, tear strength up to 107% higher, and compression set up to 91% higher), which indicates the possibility of using these materials in technological applications, such as in the civil and automotive industries.

Protective Low-Density Polyethylene Residues from Prepreg for the Development of New Nanocomposites with Montmorillonite: Recycling and Characterization

A sustainable alternative to the destination of polyethylene (PE) residue from the prepreg package was established. This work intends to develop nanocomposites for packaging containing neat low-density polyethylene (LDPE), a compatibilizer agent (maleic anhydride grafted-LDPE, LDPE-g-MA), recycled LDPE obtained from the protective films of prepreg (rLDPE) and montmorillonite (MMT). The rLDPE, from the prepreg shield, has a primary role during the transport and storage of prepreg, which can be composed of epoxy resin and carbon fiber or glass fiber. However, this rLDPE is withdrawn and discarded, besides, it is estimated that tons of this material are discarded monthly by the company Alltec Materiais Compostos Ltd. (São José dos Campos-SP, Brazil). Due to several factors, including the lack of technology for recycling, the majority of this material is incinerated. In this context, this work presents a technical and ecologically viable alternative for the use of this discarded material. Nanocomposites of LDPE/rLDPE blends and montmorillonite (MMT) with different contents (0.0, 1.0, and 3.0 wt%) and with the addition of compatibilizer agent (LDPE-g-MA) were prepared by extrusion process. Test specimens were obtained by hot pressing in a hydropneumatic press followed by die-cutting. The nanocomposites produced using rLDPE presented good mechanical, thermal, and morphological properties, being the ideal concentration of 1 wt% MMT. Thus, the results obtained confirmed the viability of recycling LDPE from the prepreg package which contributes to the reduction of waste and the use of this material in technological applications.

Blue, Green and Red Upconverted Emission of Controlled Hydrothermal Pressure Synthesized Y2O3: Er3+ (1%) Tm3+ (1%) and Different Yb3+ Ratio Conditions Nanophosphors

Introduction: Rare earth-doped Upconverting Nanoparticles (UCN's) can convert near-infrared photons into visible photons via multiphoton processes, which makes it a good material for generating white light. The production of luminescent materials for technology applications focuses on controlling powder characteristics such as chemical homogeneity and low impurity levels. Objective: In this research study, we synthesized Er3+ (1%) Tm3+ (1%) Yb3+ (at different percentages) by co-doping Y2O3 NPs, using the Controlled-Pressure Hydrothermal Method (CPHM), with nitrogen. The ratio used was chosen to conduct a detailed photolumniscence analysis. Methods: Samples of Y2O3: Er3+ (1%) Tm3+ (1%) Yb3+ (at 1.5%, 2%, and 2.5%) were prepared using the controlled-pressure hydrothermal method (CPHM). Each solution was transferred into a mini-clave drive Büchiglasuster with an inner Teflon vessel. In this case, the mini-clave was heated at 190°C for 3 h, and nitrogen was used to control the pressure. The initial pressure was 20 bars; it was increased during the process to 42 bars. The powders obtained were washed with distilled water using centrifugation at 4000 rpm for 15 min. The washed product was dried to 120°C, followed by subsequent heat treatment at 1000°C for 5 h. Results: The representative XRD patterns for the Y2O3: Er3+ (1%) Tm3+ (1%) and Yb3+ (at 1.5%, 2%, 2.5%) doped samples confirms the presence of a cubic Y2O3 crystal structure. Scanning Electron Microscope (SEM) images show that the morphology of these particles is spherical. Upconversion photoluminescence spectra of Y2O3:Er3+ (1% mol) Tm3+ (1% mol) Yb3+ (1.5% mol), Yb3+ (2.0% mol), and Yb3+ (2.5% mol), after 908-nm excitation. Blue, green, and red bands are centred at 440 nm, 469 nm, 618 nm, and 678 nm, respectively. Conclusion: The controlled-pressure hydrothermal method is a productive method for synthesizing rare earth-doped and codoped Y2O3; when Er3+, Yb3+, and Tm3+ ions are introduced into the host matrix, they do not cause any changes in the cubic structure nor influence the crystal structure. This method can used to synthesize any type of nanoparticle, because it involves low pressure (10-20 bars), low temperatures, and short time reactions.

Effective Hexagonal Boron Nitride Passivation of Few-Layered InSe and GaSe to Enhance Their Electronic and Optical Properties.

Indium selenide (InSe) and gallium selenide (GaSe), members of the III-VI chalcogenide family, are emerging two-dimensional (2D) semiconductors with appealing electronic properties. However, their devices are still lagging behind because of their sensitivity to air and device fabrication processes which induce structural damage and hamper their intrinsic properties. Thus, in order to obtain high-performance and stable devices, effective passivation of these air-sensitive materials is strongly required. Here, we demonstrate a hexagonal boron nitride (hBN)-based encapsulation technique, where 2D layers of InSe and GaSe are covered entirely between two layers of hBN. To fabricate devices out of fully encapsulated 2D layers, we employ the lithography-free via-contacting scheme. We find that hBN acts as an excellent encapsulant and a near-ideal substrate for InSe and GaSe by passivating them from the environment and isolating them from the charge disorder at the SiO2 surface. As a result, the encapsulated InSe devices are of high quality and ambient-stable for a long time and show an improved two-terminal mobility of 30-120 cm2 V-1 s-1 as compared to mere ∼1 cm2 V-1 s-1 for unencapsulated devices. On employing this technique to GaSe, we obtain a strong and reproducible photoresponse. In contrast to previous studies, where either good performance or long-term stability was achieved, we demonstrate a combination of both in our devices. This work thus provides a systematic study of fully encapsulated devices based on InSe and GaSe, which has not been reported until now. We believe that this technique can open ways for fundamental studies as well as toward the integration of these materials in technological applications.

Wear Behaviour of Aluminium Matrix Hybrid Composites: A Review

This review focus on the effect of reinforcement and different manufacturing techniques on wear and mechanical properties aluminium matrix composites and hybrid composites. These materials have capacity to satisfying the demands of advanced engineering materials applications. These difficulties are satisfied due to improved mechanical properties, conventional processing technique and reducing fabrication cost of aluminium composites. In powder metallurgy, the crucial issue is the selection of sizes of the matrix and reinforcement powders, whereas a major challenge in liquid metallurgy is wettability between the reinforcement particles and molten alloy. The addition of Al2O3 particles in matrix increases the mechanical strength and wear resistance of composites. However, incorporation of these particles can reduce the wear performance of Al composites under severe conditions. The addition of graphite particles helps in the formation of a thick layer on the wear surface. It was found that the mechanical and wear properties of the single reinforcement composites are better as compared to pure aluminium and aluminium alloys regardless of the aluminium matrix composites fabrication technique. Further, it was also established that most of the hybrid composites demonstrate better mechanical and tribological properties as compared to single reinforcement composites. How to cite this article:Singh S, Gupta A, Sharma. Wear Behaviour of Aluminium Matrix Hybrid Composites: A Review. J Adv Res Mech Engi Tech 2019; 6(1&2): 13-22.

Amorphous sulfide heterostructure precursors prepared by radio frequency sputtering

Two-dimensional sulfides and their heterostructures have emerged as potentially useful materials for technological applications. Controllable self-assembly of interleaved crystalline heterostructures from designed thin-film precursors has been demonstrated in selenide and telluride chemical systems, but not yet in sulfide chemistries. Preparing such amorphous sulfide heterostructure precursors is a necessary first step toward this goal. Here, deposition of thin-film amorphous precursors for layered sulfide heterostructures by RF sputtering is presented on the example of SnS-MoS2. A calibration process specific to the mechanisms of RF sputtering from sulfide and disulfide compound targets is established. Precursor film structure and composition are confirmed via x-ray reflectivity and Rutherford backscattering measurements. Local nanostructure and composition are also examined by electron microscopy and electron energy loss spectroscopy.

Editorial Preface on the Proceeding of International Conference on Design and Application of Engineering Materials (IC-DAEM).

International Conference on Design and Application of Engineering Materials 2018 (IC-DAEM) was the first international conference initiated by Materials Science and Engineering Research Group, Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung, Indonesia. The conference was held in Bandung Indonesia on 6th – 7th September 2018 in conjunction with annual national meeting entitled Seminar Nasional Metalurgi dan Material XI 2018 (SENAMM XI). The theme of the conference was “Emerging the knowledge of materials design to achieve better materials integrity” and was held as an honour for the retirement of Prof. Mardjono Siswosuwarno, which is considered as one of the pioneers in the field of failure analysis in Indonesia.The topics of interest of IC-DAEM 2018 included but were not limited to: materials design, development of synthesis and characterization method, experimental and computational work related to this topic, application aspect of engineering materials including materials degradation and failure analysis. Four keynote lectures were delivered on the topics of Production of Rare Earth Ortho-Ferrites from end-of-life Nd Magnets, Characterization of Calcium Phosphate Ceramics Synthesized by Heterogeneous Nucleation for Artificial Bone Substitutes, Development of Steel Matrix Composites Used for Metallic Die, and Effective Steps in Performing Failure Analysis.Papers presented in IC-DAEM 2018 are included in this proceeding after going through peer reviewing process. This proceeding contains papers with broad topics on design and application of engineering materials, such as (1) Inspection, Maintenance, Techniques and Managements, (2) Method and Case of Engineering Failure Analysis, (3) Time Dependent Properties and Degradation of Engineering Materials, (4) Computational Modelling and Simulation, (5) Development of Synthesis and Characterization Methods, (6) Laboratory and Full Scale-Scale Experiments, (7) Materials and Alloy Design, and (8) Materials Property Improvement. We hope that these papers will immensely benefit the research community working in Materials Science and Engineering, both in the academic and industrial fields.

Experimental and numerical evaluation of the temperature profile of a modular extrusion head applied to an experimental 3D printer

This paper presents a thermal numerical model based on experimental evaluation of the temperature profile of an experimental 3D printer extrusion head. The experimental 3D printer offers the option of changing the deposition head subsystem, enabling the usage of different kinds of feedstock. The study developed in this work focused on a single screw extrusion head in which feedstock is supplied on powder form. The use of polymeric powder with fillers and additives supports the exploration and improvement of material engineering applications, including 4D printing. The first step was the development of an instrumentation system for the in loco monitoring of the temperature profile of the extrusion subset. Thermo-graphic images were generated in order to complement the experimental evaluation of the temperature profile. Simultaneously, a numerical thermal model of the extrusion head was elaborated using a commercial CAE program. The comparison between experimental and preliminary numerical results enabled the fitting of the thermal computational model. The main contribution of this work was to provide a computational thermal model, fitted by experimental procedure, capable of estimating the temperature profile of a modular single screw extrusion head applied to an experimental 3D printer. The iterative fitting between the experimental results and numerical analysis improved the assertiveness of the computational model from 54 to 85%.