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In this study, the process for the development of the high-density polyethylene (HDPE) and the Aluminium (Al) powder-reinforced composites has been outlined by the single screw extruder for the feedstock filament study. The filament has been prepared on the single screw extruder. The study is illustrated with two different stages: (a) melt flow index (MFI) of 10g HDPE reinforced (0%–50%) with varying concentrations of Al-powder and (b) extrusion of the filament utilizing the ratio of 75% HDPE and 25% Al-powder for distinguished experimental parameters. The result of this study suggests the best filament extrusion setting for the different heat-treated and nonheat-treated conditions for Young’s modulus. The extrusion parameters are $146^{\circ }$C, $150^{\circ }$C for heat-treated (HT) and nonheat-treated (NHT) conditions at a nozzle diameter of 1.75mm. The result has been supported by universal testing machine (UTM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). HDPE-Al-2 has the highest mechanical properties $150^{\circ }$C at 6rpm heat treated. The crystallinity of the filament increased to 64% with the Al-powder reinforcement along with enhancement of the properties of Young’s modulus of heat-treated samples.

This work investigates the time-dependent squeezed and extruded flow of viscous incompressible and electrically conducting fluid between two convective parallel plates under an impressed transversely applied magnetic field. The governing nonlinear partial differential equations are reduced to dimensionless form using some selected dimensionless parameters and solved numerically in Matlab. A detail analysis illustrating the influence of various governing parameters like extrusion, squeezing, Eckert, Hartmann number, dimensionless time and Biot number on fluid velocity, normal fluid velocity, temperature, rate of heat transfer and local coefficient of skin friction are highlighted and discussed. The results reveal that rate of heat transfer and coefficient of local skin friction can be optimized by increasing/decreasing the squeezing parameter. Also, the result also reveal that increasing the extrusion parameter and the Hartmann number reduces the rate of heat transfer and enhances the coefficient of local skin efriction.

Natural fibre reinforced thermoplastic composites find a wide array of applications in the automobile, building and construction industries. These composites are mostly produced by injection moulding or extrusion through properly designed dies. During these production processes, the shear forces exerted by the screw or ram leads to the degradation of the natural fibres. A screwless extruder that minimises fibre degradation and employs a reliable and low technology process has already been developed. However, the fibre degradation caused by the screwless extruder has not been compared with that of the conventional extruders. So, this study is focused on the influence of extrusion processes on the degradation of natural fibres in thermoplastic composites. Sisal fibres of 10 mm length were extruded with polypropylene, to furnish extrudates with a fibre mass fraction of 25%, using conventional single screw and screwless extruders. Polypropylene in the extrudates was dissolved in Xylene in a Sohxlet process; the fibres that were extracted were analysed for length variations. While fibre degradation in the form of fibre length variation is similar in both cases, this can be minimised in screwless extrusion by extending the gap between the front face of the cone and the orifice plate.

Microstructural characterization of as-cast and extruded experimental alloys as (A) Mg-6.86Li-3.02Al-1.12Ce-0.7Ca (B) Mg-8.15Li-3.07Al-1.12Ce-0.72Ca (C) Mg-10.54Li-3.54Al-1.23Ce-0.94Ca are researched in this paper. The results show that the as-cast specimens of (A) and (B) are composed of α (Mg) phase, β (Li) phase, rod-like and bulk Al₂Ce compound. On the other hand, β phase (Li), bulk and rod-like Al₂Ce compound, Al²Ca compound at boundaries are observed in the as-cast (C) alloy. The addition of Ce and Ca also shows in the microstructure the presence of Al-Ce-Ca phase, a solid solution of Ca in Al2Ce compound. In the extruding alloys, the microstructure is refined and the β phase has the effect of coordination during deformation. The long rod-like and the bulk compounds become short rods and fine clumps distributing evenly in the extruding direction after extruding process. The microstructure of extruded Mg-10.54Li-3.54Al-1.23Ce-0.94Ca alloy testified the existence of eutectic structure.

As-cast ZK60 magnesium alloy that has been treated by homogenizing was forward extruded at 380°C and different extrusion ratios. Half of the extruded samples were treated by T5 treatment (10 hours at 170°C). The microstructure and mechanical properties of extruded samples that have been treated by T5 treatment and not been treated by T5 treatment have been measured. Experimental results show that the T5 treatment of extruded ZK60 magnesium alloy will cause the tensile strength and hardness to increase in some sort, the yield strength to increase obviously, but elongation to decrease slightly. When ZK60 magnesium alloy is extruded at 380°C, the second phase, MgZn and a small quantity of MnZn₂, will precipitate, and the distribution of second phase is even and dispersed. After T5 treatment, the change of grain size is not obvious, but the quantity of precipitated phase obviously increases comparing with extruded samples, and some of the precipitated phase aggregate and grow.

Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technique that extrudes highly ceramic loaded aqueous paste along 3D contours for complex ceramic part fabrication. The phenomenon of liquid phase migration (LPM) in paste extrusion process will result in variation of liquid content in paste and consequently problems in processing and non-uniform properties of ceramic parts. It is necessary to understand the LPM phenomenon in FEF process. In this paper, the effect of liquid phase migration on extrusion of aqueous alumina paste was investigated for FEF process. The water content and extrusion force data were collected for a series of ram velocities. According to the extrusion force profiles, the extrusion process can be divided into four stages: compaction stage, transient stage, steady stage and dead zone stage. The results show that ram velocity is the key parameter for occurrence of liquid phase migration phenomenon and there is a velocity threshold above which the liquid phase migration will not happen.

The magnesium silicide precipitates in the 6XXX series alloy are the main components contributing to the heat treatable properties and T6 strength of the alloy, which is influenced by the size, morphology and distribution of this phase. During the extrusion process, the strength contributing phase, magnesium silicide is supposed to dissolve and form again in a controlled state during age hardening. Whereas the intermetallic AlFeSi phase has little if any influence on the strength, the β phase of this intermetallic is known to cause brittle fracture of this alloy, as opposed to the less detrimental, more equiaxed α phase formed during homogenisation.

This study investigates the as-extruded 6060 and the more heavily alloyed 6261 aluminium alloys, as well as the subsequent heat treated forms to investigate the ageing conditions to optimise hardening and shorten age hardening times for higher cost effectiveness. The microstructure, texture and precipitate size and distributions were studied using optical microscopy, SEM, EBSD and DSC. SEM and EDAX results have indicated signs of evenly distributed α AlFeSi and β Magnesium Silicide precipitates. The phase responsible for hardening is believed to be the much smaller scaled β" magnesium silicide, requiring much higher resolution studies.

Extruded samples of ${\mathrm{\text{Bi}}}_{85}{\mathrm{\text{Sb}}}_{15}$ solid solutions doped with 0.0005 at.% Te were obtained and the electrical conductivity $(\sigma )$, thermoelectric power (Seebeck) $(\alpha )$, Hall $(R_h)$ and thermal conductivity $(\chi )$ coefficients were investigated in the range $\sim 80$–300 K samples and magnetic field strength up to $74\times 10^4$ A/m, as annealed after extrusion, non-irradiated with gamma-quanta and the same samples irradiated with gamma quanta at different doses. It was found that at low doses (1 Mrad) of irradiation, radiation defects (RDs) appear in the samples which play the role of donor centers, as a result of which the concentration of free electrons $n$, and, consequently the electrical conductivity $\sigma$ increases, and the Seebeck coefficient $\alpha$ decreases. These defects, scattering the current carriers, reduce their mobility $\mu$. With an increase in the radiation dose, the concentration of defects also increases and free carriers are captured at the level of the RD. In this regard, the concentration of charged carrier defects $n$ and, consequently, $\sigma$ of the sample decrease, while the Seebeck coefficient and mobility increase. The effect of a magnetic field on the electrical and thermal parameters of extruded solid solution samples also depends on the radiation dose in the sample.

The electrical and thermal properties of extruded samples of Bi${}_{85}$Sb${}_{15}$$〈\mathrm{\text{Te}}〉$ modified with ZrO₂ were investigated depending on the dose of gamma radiation in the temperature range $\sim 80÷300$ K and magnetic field strength (H) $\sim 74\times 10^4$ A/m. It was found that an increase in the mobility in the irradiated modified Bi${}_{85}$Sb${}_{15}$$〈\mathrm{\text{Te}}〉$ is associated with the radiation introduction of acceptor (negatively charged) centers, which at low doses are generated mainly in the regions of the efficiency of impurity scattering of charge carriers and partially neutralized centers and, accordingly, to a certain increase in the mobility. In the extruded modified samples of the Bi${}_{85}$Sb${}_{15}$ solid solution, irradiation with gamma quanta results not only in the generation of radiation defects (RDs) (centers), but also accompanied by their rearrangement. This causes a change in the spectrum of localized states and the electron scattering process, which leads to corresponding changes in the presented electrical and thermal parameters.

The rapid growth in the usage of polymers/polymer composites demands innovative welding techniques for joining. In this research work, Polypropylene (PPE) is chosen as the thermoplastic matrix and the filler selected is Spheri Glass 3000 (SGE) at 2.5wt.%. In this work, Friction Vibration Joining (FVJ) is used for joining PPE/SGE composites. The FVJ experiments were carried out according to Taguchi ${\text{L}}_{27}$ orthogonal array with input parameters as (i) Tool Profile (TP), (ii) Frequency of Vibrating Tool (FVT) and (iii) Feed Rate of Workpiece (FRW). The joints were analyzed mechanically (tensile strength, impact strength and shore D hardness) and metallurgically (scanning electron microscope). Analysis of Variance (ANOVA) is used for studying the significance of the input factors over output factors. The mechanical characteristics of FVJ joints were optimized by Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).

In this paper, upper bound solutions for plane-strain extrusion and plug drawing are presented using rigid-triangle velocity fields, assuming both the shear friction ($\tau =mk$) and the Coulomb friction ($\tau =\mu p$) conditions at the interfaces. For shear friction condition, the solutions are obtained following the classical approach. For this case, the energy dissipation rates of individual triangles are shown to be equal. For Coulomb friction condition, the analysis is carried out by the generalized upper bound formulation proposed by Collins. The energy dissipation rates of the individual triangles, in the deformation zone, for this friction condition, are found to be in geometric progression. Formulae are provided for the calculation of the lengths of contact and the contact pressures at the die/metal and plug/metal interfaces. Results are presented for mean extrusion/drawing stresses, as a function of reduction, for specified friction conditions and die/plug geometry. Values of optimum die/plug angles are determined graphically for given reductions and friction conditions. Finally, results for an alternative velocity field are presented for which the contact pressures on the die and the plug are nearly equal. The theoretical values are compared with some numerical and experimental results available in the literature.

A 17-year-old patient had a traumatic extrusion of 10 cm distal radial segment. The segment of bone was replaced after cleaning and autoclaving. At four years follow-up, there was complete incorporation with almost full functional recovery. We report this case for its rarity and successful result.

The present study describes a method to fabricate polymer matrix nanocomposites by reinforcing multi-walled carbon nanotubes through an extrusion process. Linear low density polyethylene (LLDPE) powder and multi-walled carbon nanotubes (CNTs) are first dry mixed and extruded in the form of filaments by a single screw extrusion process. After extrusion, the filament is partially cooled by chilled air, dried, and continuously wound in a spool. The filaments are then laid in roving, stacked in a unidirectional fashion, and consolidated in a compression molding machine to come up with laminated composites. Thermo gravimetric analysis (TGA) has been performed to compare the thermal stability of as-fabricated composites with the neat polymer. The TGA result shows that the extruded composites are thermally more stable than their neat counterparts. The crystalline nature of CNTs and of as-fabricated composites were identified by X-ray diffraction (XRD) studies. The XRD results indicate that the nanocomposite materials are more crystalline than the neat systems, and the differential scanning calorimetry studies also confirmed the same trend. The scanning electron microscopy result showed that the sizes of extruded neat and nanophased filaments were about 117 and 73 μm, respectively. Tensile coupons from the consolidated panels were then extracted both in longitudinal (0°) and in transverse (90°) directions and tested in a Minimat Tester. It was found that with the addition of 2% by weight of CNTs in LLDPE, the tensile strength and modulus of the composite has increased by about 34 and 38%, respectively. The (0°) and (90°) coupons have also demonstrated that there are directional effects in the tensile response, which is believed to have been caused by the alignment of CNTs during the extrusion process. It is our understanding that such improvement in properties is because of the increase in crystallinity of the polymer due to CNT infusion, and also due to the alignment of CNTs in the extrusion direction in the nanocomposites. Details of the fabrication procedures, synthesis of composites, and mechanical testing are included in the paper.

The preparation of high-impact polypropylene nanocomposites with different organo-montmorillonite (O-MMT) contents by means of meltprocessing was investigated. The nanocomposite properties were evaluated by transmission electron microscopy (TEM), flexural modulus, izod impact strength, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was noticed that the PP/O-MMT nanocomposites properties were affected by clay content. Exceptional improvements in impact strength were obtained (maximum of 185%) by the use of low O-MMT content. The results showed that higher enhancement on mechanical/thermal properties was obtained by 3 wt.% of O-MMT instead of higher quantities.

Recent developments in the field of manufacturing techniques and alloy development of light materials are reviewed. In the field of manufacturing Aluminium based components, special attention is given to casting, including liquid forging and semi-solid forming technology while for sheet metal forming technology the focus is on material properties and process technology in superplastic forming. For the manufacturing of Magnesium-based components, special attention is given to casting processes and alloy development for casting. For wrought Magnesium, material properties control is covered. For Titanium-based components, an overview of the latest additions to high strength alloys are given, including non-linear elasticity as demonstrated by materials like GUM Metal™. Advanced forming technology such as Levi Casting are also treated.

A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.

Surgeons and patients are demanding improved replacements for dysfunctional ossicular bones. Replacement of the entire ossicular chain and positioning the prosthesis between the stapes footplate and the tympanic membrane are of particular challenges. Many materials have been used since the first ossicular replacement; at the present time, the two most widely used materials are titanium and hydroxyapatite. Studies have indicated little difference between these two materials. A variety of novel additions have been added to total ossicular replacement prostheses to overcome limitations associated with conventional prostheses. Testing of novel prosthesis materials and designs over long time intervals is needed in order to validate and expand their usage.

In this paper, backward and forward–backward-radial extrusion processes of aluminum have been simulated using finite element method. Due to the extreme deformation of the workpiece and the restrictions of the Lagrangian approach to simulate such problems, the arbitrary Lagrangian–Eulerian (ALE) and the Eulerian descriptions have been implemented in backward and forward–backward-radial extrusion processes, respectively. Operator-split method is used to solve the coupled governing equations of the Eulerian and the ALE formulations. To validate the finite element simulations, the results have been compared with experimental data in terms of extrusion load and geometry of final products. A good agreement has been seen between the results demonstrating the capability of the Eulerian and the ALE methods on finite element simulation of extrusion processes.

Dense aluminum-lithium alloy reinforced with up to 20 vol.% SiC_p was prepared from powder mixture using spark plasma sintering process (SPS process). The process, originally developed by Sumitomo Coal Mining Co., has been found to be highly effective for the sintering of ceramic, metallic, and composite materials. Aluminum A 8090 was mixed with silicon carbide particles (SiC_p) by mechanical milling before sintered at 723 K under a pressure of 125 MPa for up to 10 minutes. Relative density of the sintered composite reinforced with 10 vol.% SiC_p was found to exceed 99% of the theoretical value. The Young modulus, yield stress, and ultimate tensile stress of the composite were 91 GPa, 256 MPa, and 332 MPa, respectively, which are, approximately, of the same values as those conventionally hot-isostatic press processed. The elongation of the composite was also found to be higher than that of the conventional one. The microstructure of the sintered composite was observed using both optical and scanning electron microscope. In the region away from the contact surface with the mould wall, the matrix powder was compressed along the vertical direction and elongated in the horizontal direction normal to the applied pressure. At the surface where the specimen was in contact with the mould and punch, the friction force controlled the deformation and thus the shape of the sintered powder. In this paper, the influences of reinforcement volume fractions, sintering temperatures, holding time, and applied pressure are also discussed.

The demand for materials of superior properties is increasing day by day. Due to this materials scientist are developing new materials to meet the demand of growing need of materials. The material scientist for the development of metal matrix composite has been given much attention, which are continuously replacing traditional materials. There are several fabrication techniques for the production of MMC. Among the fabrication processes of MMCs of recent development, powder metallurgy is one of the most widely used fabrication techniques. Powder Metallurgy (P/M) offers designers and users a versatile and efficient method of producing components. The process is versatile because it can be used for simple and complex shapes, and a full range of chemical, physical and mechanical properties is possible to obtain. P/M is efficient because it produces moderate to high-volume net or near-net shapes, with very little raw material loss. In general, the process has very good potential to improve performance through uniform properties, fine grain structures, and chemical homogeneity. During the process, the matrix material powders and the reinforcement particles are blended to produce a homogeneous distribution and fed into a mould of desired shape, hot press to a desired level of compaction and final consolidation by extrusion, forging, rolling or some other hot working method. The powder metallurgy attracted attention of the parts manufacturer during the last decades based on progress in materials, process and equipment. The conventional powder metallurgy process consists of three main-steps: powder mixing, compacting (sintering) and extrusion. To carry out the processing of MMC through powder metallurgy, development of powder metallurgy set up is essential. Powder metallurgy set up consists of several main parts such as die, mould, in which the powder is contained, punches, which are used to apply compacting pressure and heater for hot compaction as well as hot extrusion of MMCs. The main aim of the article is to discuss model design, process planning and fabrication of powder metallurgy set up as well as heating system for hot compacting /extrusion (direct and indirect).