This work aims to define the microstructure and to study the mechanical properties of an Al matrix incorporated with various amounts of Fe2O3 (3, 6, 9, 12 and 15 wt.%) with a constant amount of Ag at 1 wt.%. Al/Fe2O3 + Ag hybrid nano-composite samples are manufactured using powder metallurgy. An aluminum matrix is considered an important alloy, owing to its properties such as being lightweight, strong and corrosion and wear resistant, which enable it to be used in many applications, such as electronics, aerospace and automotive purposes. Various examinations have been performed for the samples of this work, such as Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis to estimate the microstructure and phases of manufactured nano-composites. Mechanical testing is also carried out, such as micro-hardness testing, compressive testing and wear testing, to estimate the mechanical properties of the hybrid nano-composites. The results of FESEM and XRD demonstrate that Fe2O3 and Ag nanoparticles are uniformly distributed and dispersed into the Al matrix, whereas the mechanical tests show that enhancement t micro-hardness, compressive strength of 12 wt.% Fe2O3 + 1Ag and wear rate decrease to a minimum value of 12 wt.% of Fe2O3 + 1Ag.
This investigation aims to study the characterization of MgO nanoparticles prepared using two different routes via microwave method and sol-gel route. The characteristics of the fabricated of MgO nanoparticles were examined by FESEM, XRD, FTIR and BET. The results of XRD for microwave method and sol-gel route revealed peaks indicating the uniform crystalline. The images of FESEM of MgO nanoparticles by microwave method evinced an irregular shape, but the MgO nanoparticles synthesized by sol-gel route were found crystallites, nano spherical shape. The results of this work manifested that the MgO nanoparticles prepared via sol-gel route had smaller grain size as (≈ 50 nm) compared to the microwave method (≈ 72 nm). The specific surface area of the MgO nanoparticles using sol-gel route was more than with microwave route. FTIR examination reveals that the presence of Mg-O in the sample.
Because of the unique properties, Ni-Ti based shape memory alloys (SMAs) are increasingly attractive for a wide variety of engineering applications such as actuators, biomedical, or robot coupling. In this work, a third alloying element, namely nanoparticles of Ag (which is insoluble in Ni-Ti matrix), is added by powder technology to the Ni-Ti alloy to produce a Ni-Ti-Ag alloy. The Nanoparticles of the Ag element are added at 3, 5, 7, and 10 wt. % to produce four alloy specimens with different mixtures. The mixing process was done by a horizontal mixer for 120 min with a speed of 350 rpm, and then the mixture was compacted by using a compacting pressure of 600 MPa. Afterward, the compacted specimens were sintered at 600/min for 6 hrs. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to evaluate the microstructure and phases of the products. DSC examination was used to characterize the phase transformation temperatures in heating and cooling. Wear behavior was defined by using the pin-on-disc technique, and the hardness of the samples was calculated using Vickers's hardness apparatus. The results of this work showed that the nano-Ag added at 7 and 10 wt. % were distributed homogeneously in the Ni-Ti matrix, and that Ag slightly decreased hardness and increased the wear rate. The value of shape memory effect (SME) for the produced alloy was about 89.9% and the phase transformation in heating was at a temperature of about 186.48 and in cooling of about 140.3 for the specimen that contains 10 wt.% Ag nanoparticles.
In this paper, shape memory alloys (SMAs) (NiTi-based) have been manufactured by casting with a different atomic percentage of a silver element (0, 1, 2 and 3 at. % Ag) using a Vacuum Arc Remelting (VAR) furnace. The silver element is added to the binary alloys due to its excellent properties such as (anti-corrosion, anti-bacterial and high electrical conductivity), which make these alloys using in wider applications. These alloys with different atomic percentages (Ni55Ti45Ag0, Ni55Ti44Ag1, Ni55Ti43Ag2 and Ni55Ti42Ag3) have been manufactured. The successful manufacturing process has been achieved and proved via examinations and tests. The FESEM microscopic examinations show that the silver element has been distributed uniformly and homogeneously in the NiTi matrix. Moreover, the emergence of austenite phase, martensite phase and little amount impurities. Regarding the XRD examination, showed that there is an increase in the number of peaks of Ag phase with an increase in the atomic percentage of the silver element, as well to emergence of phase (Ti2Ni) upon heating, phase (Ti 002) upon cooling, and phase (Ni4Ti3) is not desired. The starting and finishing of the phase transformations have been determined for all samples by the DSC test. The Shape Memory Effect (SME) for the alloy (Ni50Ti42Ag3) is measured to be about 89.99%.
In this paper, study the effects of magnetite nanomaterial Fe3O4 on the mechanical properties of epoxy. Dispersion of Fe3O4 nanoparticles in the epoxy resin was performed by ultrasonication. The samples of the nanocomposites were prepared using the casting method. The nanocomposites contain epoxy resins as a matrix material incorporated by different weight percentages of magnetite Fe3O4 that varies from 0wt.% to 15wt.% as a reinforcing material. The epoxy with the additive reinforcement materials Fe3O4 was slowly mixed in a sonication bath for 15 minutes, then the mixture poured into silicon molds. Field Emission Scanning Electron Microscopy FESEM and X-ray diffraction spectra XRD were used to characterize the morphological and structural properties of preparing samples and the distribution of Fe3O4 nanoparticles to the epoxy resin. Mechanical testing consists of tensile, hardness shore, and three-point flexural tests were performed on the samples at room temperature according to ASTM standards. The results showed that reinforcement by 15wt.% of Fe3O4 nanoparticles maximizes these mechanical properties of nanocomposites compared with pure epoxy except for the young modulus's preferred weight at 9 wt.%, this is due to aggregation of the additives nanomaterials in epoxy resin above 9 wt.%.
The purpose of the current research is to study the microstructure and mechanical properties of Ni-Ti-Ag shape memory alloys prepared by the casting route. Ag (grain size at 1 mm) was incorporated into Ni-Ti alloys at varying percentages of weight (0, 1.5, 3 and 4.5 wt.% Ag) to produce shape memory alloys using a Vacuum Arc Re-melting (VAR) furnace. Microstructural analysis was defined by FESEM microscopy and XRD examinations, while the transformation temperatures of the Ni-Ti-Ag shape memory alloy were determined by DSC examination. On the other hand, determination of mechanical properties was carried out using micro-hardness and compressive tests. The results of this work show that Ag was dispersed homogeneously into the Ni-Ti alloy. Moreover, two primary phases (austenite phase and martensite phase) emerged with few impurities. The results of the XRD examination show that the number of Ag peaks increased with the increase in weight percentage of Ag. The transformation temperature of the austenitic phase was defined as −1.6 °C by DSC. The mechanical characterizations increased with the increase in weight percentages of Ag (1.5, 3 and 4.5 wt.%), and significantly affected the mechanical properties of the Ni-Ti alloy. An improvement in compressive strength (42.478%) was found for the alloy with 3 wt.% Ag, while the micro-hardness results show a slight decrease in micro-hardness (8.858%) for the alloy with 4.5 wt.% Ag.
In this paper, specimens of Ni-Ti shape memory alloy incorporating different percentages of Ag nanoparticles are constructed and three of its properties are studied which are density, porosity, and electrical conductivity. The specimens are constructed using powder technology. The construction process involved three main steps; mixing, compacting, and sintering. Before conducting the tests necessary to reveal the alloy properties mentioned above which represent the focus of this work, the constructed ternary Ni-Ti-Ag alloy specimens were first tested to check some of its characteristics and prove that the constructed alloy is a shape memory alloy. These tests included the Differential Scanning Calorimeter (DSC) test, the X-Ray Diffraction (XRD) test, the Scanning Electro-Microscopy (SEM) test, and the Shape Memory Effect (SME) test. The results of these tests reflected the homogeneous distribution of the Ag nanoparticles in the Ni-Ti matrix and indicated the formation of the austenite (Ti2Ni) and martensitie (Ti 002) phases, and that the alloy has a very good SME (89.9% for the 10 wt.% percentage of Ag nanoparticles). Next to this step, porosity test and electrical resistance test were carried out. The results and related calculations for these tests showed that increasing the weight percentage of Ag nanoparticles decreases the porosity and increases the density as well as the electrical conductivity.
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