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The main aim of this paper is to investigate influence of the depth of cut (size of chips) in the process of an aluminium alloy turning, extrusion temperature and compaction force on process of solid-state recycling (SSR) of produced chips. SSR process consists of cold compaction of obtained chips for the purpose of producing compacted billets and their hot extrusion to produce semi- finished round bar product. An original approach to this problem is through mathematical modelling presented with the design of experiments. It was proved the influence of main researched factors on yield strength (YS) and hardness of recycled samples. The extrusion temperature of 500°C, compaction force of 500 kN, and depth of cut of 0, 5 mm are the optimal values for the best recycling results regarding YS. On the other hand increment of the depth of cut increases the hardness of samples

The presence of Al 3 Zr precipitates promotes continuous dynamic recrystallization in Al-Zn-Mg alloys during hot extrusion, resulting in a fine-grained structure. The mechanism for this phenomenon was investigated by observing the change in microstructure under hot extrusion using high resolution EBSP. In the rear of the extrusion die mouth, grain boundary mobility is low since the flow stress is comparatively low and grain boundary migration is inhibited by Al 3 Zr particles. Thus, in order to reduce the deformation-induced high dislocation density, continuous dynamic recrystallization occurs, which does not involve long-range grain boundary migration, resulting in a finer-grained structure. The flow stress, and hence, the mobility of the grain boundary increase near the die mouth. This promotes long-range grain boundary migration, which reduces the dislocation density. Continuous dynamic recrystallization is not observed under these conditions. Since Al 3 Zr precipitates inhibit long-range grain boundary migration, increase of the Al 3 Zr precipitate content expands the region where continuous dynamic recrystallization occurs towards the die mouth, resulting in a finer-grained structure.

The present work introduces a novel extrusion with filler material to produce the high-performance TiBw/Ti-6Al-4V composite tube with a quasi-continuous reinforced structure. A simulation was adopted to study the effect of the filler material on the shape accuracy of the tubes. Based on the simulation results, the flow stress of the filler material was not the important factor, but the friction coefficient between the filler and TiBw/Ti-6Al-4V composite and the canning shape were critical to the tube precision. The microstructure and mechanical performance for the as-extruded TiBw/Ti-6Al-4V composite tubes were systematically investigated. After extrusion, the transverse section microstructure of the TiBw/Ti6Al4V composite tube remained quasi-continuous and the TiBw were rotated to align the extrusion direction. Moreover, the tensile strength and elongation reached 1240 MPa and 13.5%, resulting from dynamic recrystallization and whisker rotation.

The production of ODS steels involves a powder consolidation step usually using the hot extrusion (HE) process. The anisotropic properties of extruded materials, especially in the ODS ferritic grades (>wt%12Cr), need a better understanding of the metallurgical phenomena which may occur during HE and lead to the observed microstructure. The hot working behavior of these materials is of particular interest. The methodology of this work includes the microstructure analysis after interrupted hot extrusion, hot torsion and hot compression (1000-1200°C) tests of ferritic steels with 14%Cr and different amounts in Ti and Y2O3.The microstructure evolution during hot extrusion process is associated with continuous dynamic recrystallization (CDRX). It leads to the creation of new grains by the formation of low angle boundaries, and then the increase of their misorientation under plastic deformation. The investigations highlight also the role of precipitation on the kinetics of this mechanism; it remains incomplete in the presence of fine and dense nanoprecipitates. After hot deformation in torsion and compression, it is noticed that both precipitates and temperature deformation have a significant impact on the deformation mechanisms and microstructure evolution. Indeed, the CDRX is dominant when temperature and amount of reinforcement are limited. However, when they are increased, limited microstructure evolution is observed. In this case, the results are interpreted through a mechanism of strain accommodation at grain boundaries, with low dislocation activity in the bulk of the grains.; L'élaboration des aciers ODS fait appel à une étape de consolidation par filage à chaud. Les propriétés très anisotropes de ces matériaux à l'état filé, notamment les nuances purement ferritiques (>12% Cr), nécessitent une meilleure compréhension des effets du procédé de filage sur la microstructure. Ainsi, ce travail de thèse a pour objectif principal d'étudier les évolutions de la microstructure lors de la transformation à chaud des aciers inoxydables ODS ferritiques, et plus globalement de comprendre le comportement de ces matériaux sous sollicitation mécanique à haute température. Pour cela, des essais de filage interrompus et des essais thermomécaniques de torsion et de compression à chaud (1000-1200°C) ont été réalisés sur plusieurs aciers ferritiques à 14% de Cr présentant différents taux de renfort en titane et en yttrium. Les microstructures obtenues après déformation ont été caractérisées par EBSD.L'ensemble des analyses microstructurales effectuées montre que la mise en forme à chaud des aciers ferritiques par filage s'accompagne d'une recristallisation dynamique de type continue. Après formation des sous-joints par restauration, leurs désorientations continuent à croître, et ceux-ci se transforment graduellement en joints de grains au cours de la déformation. La cinétique de ce mécanisme semble néanmoins fortement influencée par les caractéristiques de la précipitation présente dans le matériau ; la recristallisation devenant moins complète lorsque les précipités sont plus fins et plus nombreux. En plus du taux de renfort, l'étude de la déformation de ces nuances en torsion et en compression dans des conditions proches de celles observées en filage révèle également une forte influence de la température sur leur comportement. Les microstructures de déformation présentent une évolution d'autant plus importante que la température et/ou le taux de renfort sont limités. À 1000°C, les évolutions observées indiquent la présence de la recristallisation dynamique continue. En revanche, lorsque l'on augmente la température et/ou le taux de renfort, la déformation s'accompagne d'une évolution limitée de la microstructure, notamment en torsion où un endommagement sévère aux niveaux des joints de grains est observé. Dans ce cas, les résultats sont interprétés par un mécanisme d'accommodation de la déformation au voisinage des joints de grains. Les paramètres rhéologiques calculés à partir de ces essais mécaniques confirment la tendance à une faible activité plastique au sein des grains dans les nuances renforcées.

Within a wide project aiming at the production of fully bioabsorbable endovascular stents, cylindrical preforms of the AZ91 Mg alloy produced by SPS were submitted to hot extrusion tests. It has been found that hot extrusion produced a consolidation of the material accompanied by the occurrence of dynamic recrystallisation and a corresponding noticeable grain refinement. The microstructural characterisation revealed that the optimal extrusion conditions were 380°C and 20 mm min−1. Hot compression tests were also carried out to help in the explanation of the extrusion results and, in particular, to evaluate the friction coefficient during extrusion. It has been found that the lubrication should be improved to further optimise the process and obtain a product with superior quality.

Sintered Cu-40mass%Zn (brass) alloys with a high tensile strength and excellent machinability have been developed via a powder metallurgy (P/M) process. They are environmentally benign because fine graphite particles are included instead of lead (Pb) to improve their machinability. The effect of the content and particle size of the graphite on the mechanical properties and machinability are investigated in this paper. When applying a conventional P/M process consisting of the cold compaction and hot extrusion to consolidate elementally pre-mixed mixture of Cu-40mass%Zn and graphite powder, the addition of 1 mass% graphite particles with 5～10 μm in diameter is suitable to obtain a high tensile strength and good machinability at the same time

The composites metal matrix exhibit properties that are of great interest to the mechanical and aerospace industry, especially when it incorporates low weight with high strength. Currently, the composites ductile matrix reinforced with nanoparticles of amorphous and quasicrystalline alloys have been studied intensively. One reason is that quasicrystals exhibit aperiodic crystal structures, a fact that gives these materials unique properties such as low friction coefficient, high hardness, among others. In these work, the effect of extrusion variables in the production of aluminum composite reinforced with 0%, 3%, 6% and 20% quasicristal Al59,2Cu25,5Fe12,3B3 alloy has been studied. The composites were obtained by mechanical alloying with balls mass ratio 10:1, with rotation of 200rpm, in the period of 3h. The powder mixtures were conformed by hot compaction and extrusion. The analysis carried out by scanning electron microscopy (SEM) showed good distribution of quasicrystalline particles in the aluminum matrix, but was not detected the presence of formation of quasicristal interface with the matrix. It was observed that there was in increases in hardness of the composite increases with the fraction of reinforcement in the matrix, and also with increasing temperature and the rate of extrusion.The maximum resistance to traction was 196MPa, reached with 6% composite reinforcement. It was also found that the tensile strength increases with increasing temperature and mainly by increasing the rate of extrusion. It was found that for the pure aluminum the maximum resistance occurs for the extruded at 450°C. Thus it can be concluded that increasing extrusion temperature of 400°C to 500°C accompanied the increase in extrusion ratio from 2:1 to 3:1 provides improvements in the mechanical properties of the aluminum-quasicristal composite obtained by mechanical alloying and conformal by compaction and extrusion. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Os materiais compósitos, com matriz metálica, apresentam propriedades que são de grande interesse para a indústria mecânica e aeroespacial, principalmente, quando se incorpora o baixo peso com alta resistência mecânica. Atualmente, os compósitos com matriz dúctil reforçada com nanopartículas de ligas amorfas e quasicristalinas têm sido estudados intensivamente. Um dos motivos é que os quasicristais apresentam estruturas cristalinas aperiódicas, fato que confere a esses materiais propriedades única como o baixo coeficiente de atrito, elevada dureza, entre outras. Neste trabalho estudou-se o efeito de algumas variáveis de extrusão no processamento de compósito de alumínio com reforço volumétricas de 0%, 3%, 6% e 20% de quasicristal da liga Al59,2Cu25,5Fe12,3B3. Os compósitos foram obtidos por moagem de alta energia com razão massa bolas de 10:1, com rotação de 200rpm, no período de 3h. Os pós das misturas foram conformados por compactação e extrusão a quente. As análises realizadas por microscopia eletrônica de varredura (MEV) apresentaram boa distribuição das partículas quasicristalinas na matriz de alumínio, porém não foi verificada a presença da formação de interface do quasicristal com a matriz. Observou-se que houve aumento da dureza do compósito com o aumento da fração de reforço na matriz e, também, com o aumento da temperatura e da razão de extrusão. A resistência máxima a tração foi de 196MPa, atingida com compósito de 6% de reforço. Identificou-se também que resistência a tração eleva-se com o aumento da temperatura e principalmente com o aumento da razão de extrusão. Verificou-se que, para o alumínio puro a resistência máxima ocorre para os extrudados a 450ºC. Com isso pode-se concluir que o aumento da temperatura de extrusão de 400ºC até 500ºC acompanhada do aumento da razão de extrusão de 2:1 para 3:1 proporciona melhorias nas propriedades mecânicas dos compósitos alumínio-quasicristal obtidos via moagem de alta energia e conformado por compactação e extrusão a quente.

Pri vročem iztiskovanju izdelkov iz aluminija in aluminijevih zlitin je bistvena kvaliteta površine in ustrezna mikrostruktura. Velik pomen za doseganje zahtevane kvalitete ima mazanje. Mažemo lahko orodje ali material - okroglico. V okviru diplomskega dela so bile opravljene raziskave vpliva režima mazanja materiala na kvaliteto površine in mikrostrukturo iztiskancev. Ker se z mazanjem pred iztiskovanjem mazivo prenese na orodje, se na ta način mažejo tudi naslednje palice pri iztiskovanju. Z ustrezno količino maziva in frekvenco mazanja okroglic lahko zagotovimo konstantnost kvalitete površin iztisnjenih palic. To je bil tudi cilj moje diplomskega dela, v katerem sem kot mazivo uporabil keramični sprej SOGELUB MD 2000, katerega osnova je borov nitrid. Rezultati raziskav kažejo, da mazanje ugodno vpliva na kvaliteto površine iztisnjenih palic, mikrostrukturo v površinskem sloju, podaljša življensko dobo orodja in izboljša ekonomičnost proizvodnje. In hot extrusion of products made of aluminium and aluminium alloys, the quality of surface and suitability of microstructure are essential. With the intention to reach the requested quality, lubrication is of high significance. In the praxis, tools or extruded material can be lubricated. In the frame of diploma work the influence of lubrication sequence on the surface quality and microstructure has been studied. Because of lubrication the material before extrusion, part of the lubricant is transmitted on the tool and it enables lubrication of the rods, which are next extruded. With the appropriate quantity of lubricant and frequency of lubrication the constant quality of the surface of extruded rods can be assured. This was also the aim of my diploma work where the ceramic spray SOGELUB MD 2000, based on boron nitride, has been used. Results of the research have shown that lubrication is advantageous for the quality of extruded rods and for the microstructure in the surface region. It also increases the live time of tools and improves the production economy.

In times of increasing energy costs automotive light weight construction is gaining more importance. The production of hybrid compounds by combining hot extrusion and compound forging is a promising method to successfully manufacture functional parts by applying resource-saving process steps. Investigations of the process chain of aluminum extrusion and subsequent die forging to produce steelreinforced aluminum parts were carried out. For the analysis extruded profiles reinforced with steel wires were used. Finite element analyses of the forging process were carried out in order to predict the position of the wires within the forged parts depending on their initial position in the extrusions. Furthermore, the grain-size distribution and the joining zone between the steel wire and the aluminum matrix before and after the forging process were investigated.

The amorphous Cu46Zr42Al7Y5 alloy presents large supercooled liquid region (ΔT X = 100 K), with a viscosity of about 10(6) N.s/m² where the material can flow as a liquid, making it possible an easy deformation in this temperature region. The aim of this work was to analyze processing routes to produce bulks of metallic glasses. Two kinds of materials were used: amorphous powders and ribbons, both were consolidated by hot extrusion in temperatures inside the range between Tg and Tx, with a ram speed of 1 mm/min and extrusion ratio of 3 : 1. Analysis of X-Ray Diffratometry (XRD), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM), revealed that the proposed consolidation routes were effective to produce large bulks of amorphous materials, even with the strong decreasing of ΔT X observed after deformation by milling and during extrusion.

Определены параметры горячего прессования и последующей экструзии для получения брикетов и прутков из сыпучей стружки меди с добавками графита, обеспечивающие устойчивое течение материала при экструзии и волочении. Установлено максимальное количество вводимого в композиционную смесь графита. Составлен маршрут волочения, получена проволока различных диаметров из медно-графитовых прутков. Исследованы структура и свойства полученных изделий. The parameters of the hot-pressing and subsequent extrusion to produce bricks and bars of loose chips of copper with additives of graphite, providing steady flow of material during extrusion and drawing. Set to the maximum number of input in the composite mixture of graphite. Compiled by drawing a route and obtain a wire of various diameters of the copper-graphite rods. The structure and properties of these products.

Three innovative extrusion processes are presented: Extrusion of profiles with variable shapes, 3D curved profile extrusion for the manufacture of profiles with complex contours, and helical profile extrusion for the manufacture of twisted profiles. All these processes are based on influencing the material flow inside and behind the extrusion die. These procedures profit from the fact that only a very low load is needed to deflect the material flow in order to produce complex variable geometries. The results of experimental as well as numerical investigations are presented. The process limits and examples of extruded parts are also shown. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Las aleaciones a base de aluminio con estructura amorfa y/o nanocristalinas tienen mejores propiedades mecanicas, cuando se comparan con las aleaciones convencionales. En su obtencion se pueden utilizar diferentes tecnicas, como la solidificacion rapida (melt-spinning), donde el material se obtiene en forma de cinta y la pulvimetalurgia, que partiendo de polvos atomizados u obtenidos por molienda, se pueden conseguir piezas con geometrias y formas variadas. A partir de polvos se pueden obtener muestras de mayor volumen (bulk) es decir, muestras de grandes dimensiones (en mm), mayores que las obtenidas por solidificacion rapida (

12th International Conference on Metal Forming, Date: SEP 21-24, 2008 Cracow POLAND; International audience; A study of the microstructural evolution of Zircaloy-4 (Zy-4) during hot extrusion has been performed on a small scale device mounted on a standard NITS machine. Before extrusion the billets present a Wind-manstatten lamellar microstructure. Additional data have been obtained by hot torsion tests. After hot deformation some samples have been heat treated in various conditions. Thus the fragmentated volume fraction has been quantified with optical microscopy for various strain, strain rate and temperature histories, focusing on post dynamic effects (activation and kinetics of grain growth after deformation). For describing the microstructural evolution, the model separates dynamic and post dynamic effects. The dynamic part uses a Gourdet-Montheillet approach to describe the fragmentation. The growth is described by an explicit differential Avrami approach which can model the non isothermal evolution during cooling after extrusion. The first calculations with this model provide a good prediction of the recrystallized volume fraction for several thermal and mechanical conditions

Carbon nanotubes (NTC) have been discovered in 1991 by Iijima. The selective reduction of oxide solid solutions (Al2-2xFe2xO3, Mg1-yMyAl2O4 and Mg1-zMzO with M = Fe, Co, Ni or an alloy) in H2-CH4 mixtures leads to metal particles that are nanometric even at high temperatures, thereby allowing the formation of NTC by catalytic decomposition of CH4. Composite powders NTC-Metal-Oxide are thus obtained. The study of the synthesis parameters is based on a macroscopic method involving specific surface area measurements, correlated with electron microscopy observations. We have shown that the NTC grow during the temperature ramp, above 850°C. The NTC are mostly single or double-walled and their internal diameters range from 0.8 to 6 nm, showing that only catalyst particles that are smaller than 6 nm lead to NTC. The NTC are generally present as bundles of diameter lower than 50 nm and their length can exceed 100 μm. Isolated NTC are obtained by an acidic treatment of the NTC-Co-MgO powder which entirely dissolves the oxide matrix but some of the cobalt particles, encapsulated in graphene layers, are not dissolved. A mild oxidation of the composite powder, prior to the acidic treatment, allows to increase the carbon content up to 94 at.%. Dense composites have been prepared by hot-pressing, and by hot-extrusion in order to align the NTC. Hot-extrusion is made easier in the presence of metal, and is facilitated by the simultaneous presence of the metal and NTC. The electrical conductivity of composites containing NTC is of the order of 1 S.cm-1. An electrical conduction anisotropy is measured in the case of the extruded composites, verifying the lining-up effect. The mechanical characteristics (fracture strength and fracture toughness) of the NTC-containing composites are comparable with those of the composites without NTC, although their densification is up to 10% lower. Keywords : carbon nanotubes, nanocomposites, catalytic decomposition, oxides solid solutions, nanotubes extraction, hot extrusion.; Les nanotubes de carbone (NTC) ont été découverts en 1991 par Iijima. La réduction sélective de solutions solides d'oxydes (Al2-2xFe2xO3, Mg1-yMyAl2O4 et Mg1-zMzO avec M = Fe, Co, Ni ou alliages) par des mélanges H2-CH4 nous a permis d'obtenir des particules métalliques nanométriques à température élevée sur lesquelles la décomposition catalytique de CH4 permet la formation de NTC. Des poudres composites NTC-M-Oxyde sont ainsi préparées. L'étude des paramètres de synthèse est basée sur une caractérisation macroscopique s'appuyant sur des mesures de surfaces spécifiques, corrélée à des observations en microscopie électronique. Nous avons montré que les NTC se forment lors de la montée en température, à partir de 850°C. Les NTC préparés sont pour la plupart mono ou bi-feuillets et leurs diamètres internes sont compris entre 0,8 et 6 nm. Seules les particules suffisamment petites (£ 6 nm) conduisent à des NTC. Ceux-ci sont généralement regroupés en faisceaux dont le diamètre est inférieur à 50 nm et dont la longueur peut dépasser 100 μm. Des NTC isolés ont été obtenus par traitement acide de la poudre NTC-Co-MgO mais une partie des particules de cobalt subsiste, encapsulées dans des couches de graphène. L'oxydation ménagée de la poudre, préalablement au traitement acide, permet d'augmenter la teneur en carbone jusqu'à 94% at. Des composites massifs ont été préparés par frittage sous charge, et par extrusion à chaud dans le but d'aligner les NTC. L'extrusion est facilitée par la présence de métal, et plus encore par la présence conjointe de métal et de NTC. Ces derniers confèrent aux composites une conductivité électrique de l'ordre de 1 S.cm-1. L'effet d'alignement des NTC dans les échantillons extrudés est vérifié par une anisotropie de conductivité électrique. Les caractéristiques mécaniques (charge à la rupture et ténacité) des composites incluant des NTC sont comparables à celles des composites n'en contenant pas, bien que leur densification soit jusqu'à 10% plus faible. Mots-clés : nanotubes de carbone, nanocomposites, décomposition catalytique, solutions solides d'oxydes, extraction de nanotubes, extrusion à chaud.

Carbon nanotubes (NTC) have been discovered in 1991 by Iijima. The selective reduction of oxide solid solutions (Al2-2xFe2xO3, Mg1-yMyAl2O4 and Mg1-zMzO with M = Fe, Co, Ni or an alloy) in H2-CH4 mixtures leads to metal particles that are nanometric even at high temperatures, thereby allowing the formation of NTC by catalytic decomposition of CH4. Composite powders NTC-Metal-Oxide are thus obtained. The study of the synthesis parameters is based on a macroscopic method involving specific surface area measurements, correlated with electron microscopy observations. We have shown that the NTC grow during the temperature ramp, above 850°C. The NTC are mostly single or double-walled and their internal diameters range from 0.8 to 6 nm, showing that only catalyst particles that are smaller than 6 nm lead to NTC. The NTC are generally present as bundles of diameter lower than 50 nm and their length can exceed 100 μm. Isolated NTC are obtained by an acidic treatment of the NTC-Co-MgO powder which entirely dissolves the oxide matrix but some of the cobalt particles, encapsulated in graphene layers, are not dissolved. A mild oxidation of the composite powder, prior to the acidic treatment, allows to increase the carbon content up to 94 at.%. Dense composites have been prepared by hot-pressing, and by hot-extrusion in order to align the NTC. Hot-extrusion is made easier in the presence of metal, and is facilitated by the simultaneous presence of the metal and NTC. The electrical conductivity of composites containing NTC is of the order of 1 S.cm-1. An electrical conduction anisotropy is measured in the case of the extruded composites, verifying the lining-up effect. The mechanical characteristics (fracture strength and fracture toughness) of the NTC-containing composites are comparable with those of the composites without NTC, although their densification is up to 10% lower. Keywords : carbon nanotubes, nanocomposites, catalytic decomposition, oxides solid solutions, nanotubes extraction, hot extrusion.; Les nanotubes de carbone (NTC) ont été découverts en 1991 par Iijima. La réduction sélective de solutions solides d'oxydes (Al2-2xFe2xO3, Mg1-yMyAl2O4 et Mg1-zMzO avec M = Fe, Co, Ni ou alliages) par des mélanges H2-CH4 nous a permis d'obtenir des particules métalliques nanométriques à température élevée sur lesquelles la décomposition catalytique de CH4 permet la formation de NTC. Des poudres composites NTC-M-Oxyde sont ainsi préparées. L'étude des paramètres de synthèse est basée sur une caractérisation macroscopique s'appuyant sur des mesures de surfaces spécifiques, corrélée à des observations en microscopie électronique. Nous avons montré que les NTC se forment lors de la montée en température, à partir de 850°C. Les NTC préparés sont pour la plupart mono ou bi-feuillets et leurs diamètres internes sont compris entre 0,8 et 6 nm. Seules les particules suffisamment petites (£ 6 nm) conduisent à des NTC. Ceux-ci sont généralement regroupés en faisceaux dont le diamètre est inférieur à 50 nm et dont la longueur peut dépasser 100 μm. Des NTC isolés ont été obtenus par traitement acide de la poudre NTC-Co-MgO mais une partie des particules de cobalt subsiste, encapsulées dans des couches de graphène. L'oxydation ménagée de la poudre, préalablement au traitement acide, permet d'augmenter la teneur en carbone jusqu'à 94% at. Des composites massifs ont été préparés par frittage sous charge, et par extrusion à chaud dans le but d'aligner les NTC. L'extrusion est facilitée par la présence de métal, et plus encore par la présence conjointe de métal et de NTC. Ces derniers confèrent aux composites une conductivité électrique de l'ordre de 1 S.cm-1. L'effet d'alignement des NTC dans les échantillons extrudés est vérifié par une anisotropie de conductivité électrique. Les caractéristiques mécaniques (charge à la rupture et ténacité) des composites incluant des NTC sont comparables à celles des composites n'en contenant pas, bien que leur densification soit jusqu'à 10% plus faible. Mots-clés : nanotubes de carbone, nanocomposites, décomposition catalytique, solutions solides d'oxydes, extraction de nanotubes, extrusion à chaud.

This study investigates analytically and experimentally extrusion processes of magnesium alloy hollow helical tubes by a single-cylinder extrusion machine. The plastic flow pattern of the billet inside the die with a helical shape is simulated using the finite element analysis. The effects of the die bearing length, spiral angle, extrusion speed, initial temperature, and petal number on the largest extrusion loads, the filling ratios, and the product temperature distributions are discussed. Hot extrusion experiments are conducted with a set of forming parameters chosen from the analytical results, which can generate a greater filling ratio. Sound products are obtained and microstructure observations and hardness tests are also conducted at the cross-section of the product. The experimental values of extrusion loads and filling ratios are compared with the analytical values to verify the validity of the analytical model.

In this paper different strategies of thermo-mechanical processing of aluminum profiles subsequent to hot extrusion were developed and tested. The approach for the manufacturing of locally graded aluminum profiles is given. By using the process heat of extrusion for subsequent forming and heat treatment steps, process chains for the production of graded aluminum profiles were developed and realized on an experimental scale. Due to the geometric limitations, the technology of realizing a grading In the geometry of open and hollow profiles is different. Therefore, two innovative concepts for the thermo-mechanical processing of open and hollow sections were developed, allowing electromagnetic compression and rolling to become Integrated within the process chains. Possible applications are seen In producing functionally graded products with locally adapted geometrically and mechanically adapted properties.

Proceedings of 17th International Federation for Heat Treatment and Surface Engineering Congress (IFHTSE 2008), 27-30 October 2008, Kobe, Japan

A extrusão de alimentos envolve transformações moleculares complexas que permitem grande diversidade nos produtos extrudidos existentes e nas suas propriedades físicas, químicas, sensoriais e nutricionais. Neste artigo são apresentadas aplicações atuais da extrusão na indústria alimentar, assim como as características dos produtos extrudidos e descrevem-se as interações entre os parâmetros que as influenciam. Por fim, são ainda apresentadas as tendências que se têm vindo a impor na formulação dos produtos extrudidos., Revista de Ciências Agrárias, vol. 39 n.º 1 (2016)