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Aquest projecte és la continuació directa del projecte d'Eduard Garcia Banús, “Validación del diseño de un proceso para la obtención de lodo semisólido y construcción del prototipo”.

The relation between microstructural inhomogeneity and thermal conductivity of a rheocast componentmanufactured from two different aluminum alloys was investigated. The formation of two different primarya-Al particles was observed and related to multistage solidification process during slurry preparationand die cavity filling process. The microstructural inhomogeneity of the component was quantified as thefraction of a1-Al particles in the primary Al phase. A high fraction of coarse solute-lean a1-Al particles inthe primary Al phase caused a higher thermal conductivity of the component in the near-to-gate region. Avariation in thermal conductivity through the rheocast component of 10% was discovered. The effect of aninhomogeneous temperature-dependent thermal conductivity on the thermal performance of a largerheocast heatsink for electronics cooling in an operation environment was studied by means of simulation.Design guidelines were developed to account for the thermal performance of heatsinks with inhomogeneousthermal conductivity, as caused by the rheocasting process. Under the modeling assumptions, the simulationresults showed over 2.5% improvement in heatsink thermal resistance when the higher conductivity nearto-gate region was located at the top of the heatsink. Assuming homogeneous thermo-physical properties ina rheocast heatsink may lead to greater than 3.5% error in the estimation of maximum thermal resistanceof the heatsink. The variation in thermal conductivity within a large rheocast heatsink was found to beimportant for obtaining of a robust component design. CompCast

The melting sequence of the Enthalpy Exchange Material (EEM) and formation of slurry in the RheoMetalTM process was investigated. The EEM was extracted, together with a portion of the slurry at different times before complete melting, and quenched. The EEM initially increased in size due to melt freezing onto its surface, forming a freeze-on layer. The initial growth of this layer was followed by a constant diameter of the EEM and thereafter subsequent melting. Microstructural characterization of the size and morphology of different phases in the EEM and the freeze-on layer was made. Dendritic equiaxed grains and eutectic regions containing Si particles and Cu-bearing particles were observed in the as-cast EEM. The freeze-on layer consisted of dendritic aluminum slightly tilted by about 30° toward the upstream direction, caused by the rotation of the EEM. Energy Dispersion Spectroscopy analysis showed that the freeze-on layer had a composition corresponding to a higher melting point than the EEM. Microstructural investigation of the EEM showed that the temperature rapidly increased to 495 ºC, causing incipient melting of Al2Cu and Al5Mg8Si6Cu2 phases in grain boundary regions. Following the incipient melting, the temperature in the EEM increased further and binary Al-Si eutectic started to melt to form a region of a fully developed coherent mushy state. Experimental results and a thermal model indicated that as the dendrites spheroidized and the interface at the EEM/freeze-on layer reached a mushy state with 25% solid fraction, coherency was lost and disintegration of the freeze-on layer took place. Subsequently, in the absence of the shielding effect from the freeze-on Layer, the EEM disintegrates at a higher solid fraction, estimated to be 50%. The fast and complex slurry generation in the RheoMetalTM process is a hybrid process with both rheocasting and thixocasting elements in the process.

Semi-Solid Metal (SSM) casting is a promising technology offering an opportunity to manufacture net-shape, complex geometry metal components in a single operation. However, the absence of foundry guidelines and limited design data for SSM casting makes it challenging to predict the performance of both process and components. The objective of this research was to develop and offer new solutions to material processing-related issues in the electronics industry. By investigating the opportunities afforded by the recently developed RheoMetalTM rheocasting process, a better understanding of the critical factors needed for an effective manufacturing process and optimised component characteristics was achieved. A study of the evolution of microstructure at different stages of the RheoMetalTM process demonstrated the influence of multistage solidification on the microstructural characteristics of the rheocast components. The microstructure of a slurry consists of the solute-lean and coarse globular α-Al particles with a uniform distribution of alloying elements, suspended in the liquid matrix. Additional solute-rich α-Al particles were identified as being a consequence of discrete nucleation events taking place after the initial slurry production. In the final components, macrosegregation was observed in the form of variations in the ratio of solute-lean coarse globular α-Al particles and solute-rich fine α-Al particles in both longitudinal and transverse directions. The relation between microstructural characteristics and material properties was established by determination of the local properties of a rheocast component. The fracture of a rheocast telecom component was strongly affected by microstructural inhomogeneity. In particular, macrosegregation in the form of liquid surface segregation bands and sub-surface pore bands strongly affected the fracture behaviour. Thermal conductivity measurements revealed that regions of the component with a high amount of solute-lean globular α-Al particles showed higher thermal conductivity. The effect of the local variation in thermal conductivity on the thermal performance of a large rheocast heatsink was evaluated by simulation. The results clearly show the importance of considering material inhomogeneity when creating a robust component design.

Thermal conductivity of a rheocast component made from Stenal Rheo1 (Al-6Si-2Cu-Zn) alloy was investigated in as-cast, T5 and T6 conditions. The thermal conductivity measurement in different locations showed variation of this property throughout the rheocast component. The results of microstructural investigation revealed that the ratio of solute-lean α1-Al particles formed during slurry preparation to fine solute-rich α2-Al particles formed during secondary solidification had significant influence on thermal conductivity. The reduced amount of solutes in the α1-Al particles was determined as the root cause of higher thermal conductivity. A linear relation between the fraction of precipitates and the increase in thermal conductivity was obtained and silicon in solid solution is shown to have a dominant influence. As silicon was precipitated during the heat treatment, thermal conductivity increased. For an optimal combination of thermal and mechanical properties, it is therefore important to use an ageing temperature above the temperature of Si precipitation.

The SEED technology is a commercially available rheocasting process used in the production of high quality semi-solid slurries. The process, which is currently used in the foundry industry, is still actively developed and fully supported by a team of scientists, engineers and technicians. In the later years, works were conducted toward optimizing the process and equipment. At first, the focus was on developing a simplified version of the SEED process to eliminate the so-called "drainage" phase while preserving the prime quality of the slurry produced. Improvement of some system components and integration of new features were also targeted to secure the overall equipment efficiency (OEE) and increase the process reliability. This work, backed with the optimization of process parameters and comprehensive techniques adapted for semi-solid casting, led to the consolidation and even improvement of the properties of the parts produced for common foundry alloys as 356/357 and 319. Furthermore, the non-drained SEED version was applied to the validation of the process capabilities for uncommon cast alloys, with works on AA6061 wrought alloys, high strength 206 cast alloys and Duralcan metal matrix composites. The results confirmed that the SEED process can efficiently be used in non-drained mode and achieve the same quality of slurry as the drained-mode version originally developed. © (2013) Trans Tech Publications, Switzerland., 12th International Conference on Semi-Solid Processing of Alloys and Composites, S2P 2012, 8 October 2012 through 11 October 2012, Cape Town

Recent studies regarding semi-solid casting as a viable alternative to conventional liquid metal casting have been met with considerable interest. The dual nature of semi-solid materials results in a marked decrease in internal defects otherwise associated with conventional casting methods. In recent years, the National Research Council Canada - Aluminum Technology Centre (NRC-ATC) has dedicated itself to better understanding the behaviour of semi-solid aluminum alloys, notably 357, using the SEED (Swirled Enthalpy Equilibration Device) rheocasting method. SEED is a novel process which relies on the mechanical agitation and cooling of molten aluminum to produce a semi-solid billet. This billet is then injected into a die to yield the desired cast shape. The current work focuses on the rheocasting of a 357 aluminum alloy support bracket, consisting of four rings. Material flow around a ring is known to result in a welding of the two metal fronts. Traces of porosity and oxides can sometimes be found at the weld, unless preventative measures are taken. These include the use of overflows attached to the ring via a web as well as a careful control of the casting parameters. At NRC-ATC, several parts were rheocast and then subjected to both destructive and non-destructive testing, in an effort to better understand the material flow behaviour around these rings. The results obtained are presented herein., 12th International Conference on Semi-Solid Processing of Alloys and Composites, October 8-11 2012, Cape Town, South Africa

In the present work it has been studied the microstructure and the mechanical behaviour of a material produced by rheocasting, a new semisolid industrial process which introduces important improvements in comparison to conventional routes. The microstructure of the A357 hypoeutectic Al-Si alloys has been analysed before and after material injection. In both cases the microstructure was fine and homogeneous. Tensile tests have been done with specimens machined from real rheocasted components in two conditions, without any heat treatment and after T5 heat treatment. The results were found to be better than those obtained for this alloy when produced by conventional means.En el presente trabajo se ha estudiado la microestructura y el comportamiento de material producido mediante rheocasting, una nueva vía de producción industrial, en estado semisólido, que presenta diversas ventajas respecto a los procesos más habituales. Se ha caracterizado microestructuralmente la aleación hipoeutéctica de Al-Si A357, antes y después del proceso de inyección en estado semisólido, observándose en ambos estados una estructura fina y homogénea. Se han realizado ensayos de tracción de probetas mecanizadas de componentes reales producidos mediante rheocasting, tanto sin tratamiento térmico como tras un tratamiento T5. Los resultados, en ambos casos, fueron superiores a los obtenidos, para esta misma aleación, mediante otras vías.

Nadeutektičke Al-Si legure su našle široku primenu u automobilskoj i avio industriji zbog odlične otpornosti na koroziju i habanje, niskog koeficijenta termičkog širenja, dobre čvrstoće, odličine livkosti i male gustine. Svojstva nadeutektičkih Al – Si legura zavise od karakteristika njihove livene mikrostrukture koja se mogu poboljšati mikrostrukturnim promenama. U okviru ovog rada poboljšanje mehaničkih svojstava (tvrdoće) i kavitacione otpornosti realizovani su sledećim promenama: promenom veličine, morfologije (oblika) i raspodele primarnih i eutektičkih Si čestica. Da bi se postigla transformacija dendritne u ne-dendritnu strukturu, poluočvrsli rastop AlSi18CuMgNi legure izlagan je dejstvu smicajnih sila nastalih mehaničkim mešanjem. Mešanje rastopa legure, primenom mešača oblika ploče, izvedeno je u temperaturnom intervalu između solidus i likvidus temperature sa postepenim povećanjem brzine mešanja od 500 do 1500 o/min. Odlivci kompozita AlSi18CuMgNi/SiC dobijeni su primenom kompokasting postupka. Kao ojačivač korišćen je SiC sa prosečnom veličinom čestica 30 μm. Kavitaciona otpornost materijala, kao što su legure metala, zavise od mehaničkih svojstava posebno tvrdoće. Reokast uzorci dobijeni pri većoj brzini hlađenja i smicanja pokazali su najveću tvrdoću. Vrednost tvrdoće reokast uzoraka je opadala sa porastom vremena mešanja usled aglomeracionih procesa. Kavitaciona otpornost konvencionalnih (gravitaciono kokilno livenje), reokast i odlivaka kompozita procenjena je primenom ultrazvučne vibracione metode sa stacionarnim uzorkom. Gubitak mase odlivaka za vreme ispitivanja određivan je analitičkom metodom. Mikrostruktura i morfologija oštećene površine testiranih materijala ispitivane su primenom optičkog (OM) i skenirajućeg elektronskog mikroskopa (SEM)... Hypereutectic Al-Si alloys are widely used in the automobile and aerospace industries because they exhibit excellent wear and corrosion resistance, low coefficient of thermal expansion, good strength, excellent castability and low density. The properties of hypereutectic Al-Si alloys depend on the characteristics of their cast microstructure and they can be improved by microstructure changes. In this paper, the improvements in the mechanical properties (hardness), cavitation resistance were realized with the following changes: size, morphology (or shape), and distribution of primary and Si eutectic particles. The semi-solid melt of the AlSi18CuMgNi alloy was exposed to shear forces (caused by mechanical mixing) in order to achieve transformation of dendritic into the non-dendritic structure. Mixing of the melt (active part of the paddle stirrer) was performed in the temperature range between liquidus and solidus temperatures with a gradual increase in mixing speed from 500 to 1500 rpm. Aluminium matrix composite AlSi18CuMgNi/SiC castings were prepared using the compocasting technique. The reinforcements used were silicon carbide (SiC) particles with an average size of 30 μm. The cavitation resistance of materials such as metal alloys depends of mechanical properties (especially hardness) and microstructure. The maximum in hardness for rheocast sample obtained by higher cooling rate and higher stirring speed was achieved. The hardness values for rheocast sample decrease with increasing the stirring time due to agglomeration process. The cavitation resistance of conventional, rheocast and composite castings was evaluated by using an ultrasonically induced cavitation test method. Mass loss of castings during testing time was measured by an analytical method. Microstructures and morphology of damaged surfaces of tested materials were examined using of optical microscopy (OM) and scanning electron microscopy (SEM)...

This work is a review of the different forming and consolidation methods for particulate metal matrix composites. In the first part we focus in the forming methods from raw materials while the second is centred in the consolidation from preforms in order to get the final part.En este trabajo se ofrece una revisión de los distintos métodos de conformado y consolidación de materiales compuestos de matriz metálica reforzados con partículas. En una primera parte se hace hincapié en los métodos de conformado a partir de las materias primas y en la segunda en métodos de consolidación final a partir de preformas.

The aim of this work was to test the influence of various process parameters to obtain composite materials based on the Al18Wt%Si alloy with addition of 10Wt%SiC.For a comparative analysis purposes, the samples obtained by rheocasting process were being casted with application of the rotation speed of 1500rpm, temperature of 565 degrees C and the time of 15 minutes.Having applied a combined stirring procedure from 500 - 1500rpm, it was noticed in the semisolid state that the best paricle distribution of the reinforcing material (SiC) was attained in the.metal matrix composite. The total time required for a compocasting process was 15 minutes; the samples were being casted from the temperature of 565 degrees C. cavitation damage of both composite samples and the samples obtained by rheocasting process was being determined with application of a modified vibration-cavitation equipment. A mass loss and an analysis of the sample surface during the experiment were used as an indicator to determine the level of sample damage caused by cavitation. Test results show a very good resistance to cavitation of composite materials, facilitating a possibility to apply these materials in the conditions demanding cavitation resistance. In the case of rheocasting samples, cavitation resistance is conditioned by presence of porosity leading to faster wear.

Hypereutectic Al-18wt%Si alloy was obtained by conventional and rheocasting procedure at cooling rate 0.16 +/- 0.05 degrees Cs-1. Samples of rheocasted alloy were obtained at two stirring speeds 1000 and 1500 rpm. Tests showed that two major changes of microstructural properties of rheocasting alloy, in comparison with conventional alloy, are change of dendrite morphology into nondendrite one and change of primary phases size (alpha-Al and Si). Both changes of primary particles were monitored in area near the stirrer and at a small distance from the crucible wall. Test showed that sizes of primary, alpha-Al particles decreased with stirring speed increment, while roundness of particles increased with stirring speed increment. Stirring speed change led to different degree of primary Si particles agglomeration. At stirring speed 1000 rpm, Si particles are uniformly distributed, while at speed 1500 rpm, a tendency to form clusters is more expressed. Test results were discussed on basis of utilizing fragmentation-agglomeration mechanism of primary phase evolution in a semi-solid melt, which may contribute to explanation of semi-solid structure development.

This paper presents an analysis of an advanced squeeze casting process suitable for the manufacturing of high performance industrial components more quickly and cheaply. After a short description of the process, some produced components are considered. The components, in A380 alloys, have been T6 heat treated and their soundness has been certified by non destructive tests. All considered components have been designed for advanced application in the automotive field, in particular for quite important sport cars. Standard samples for tensile and impact tests have been machined directly from the previous components. After the execution of the tests the fracture surface of samples has been observed by SEM in order to analyze details and to evaluate the influence of the process and of the alloy on the fracture behavior. On polished transverse sections of samples the microstructure of the alloy has been observed, highlighting a mainly globular shaped microstructure as expression of the attained semi-solid conditions during the processes. A critical analysis has been developed to evaluate the real potential and to present some criticism of the process.

En el presente trabajo se realizará el estudio del estado actual de los diferentes procesos existentes de agitadores mecánicos para proceder al diseño, desarrollo, fabricación y puesta en marcha de un agitador mecánico que se utiliza en la conformación de materiales en estado semisólido Rheocasting. Actualmente estos agitadores están limitados a una cierta temperatura de trabajo y un cierto tiempo de exposición a esta, dependiendo del material en el que están fabricados. Por lo tanto estos están formados por una estación que dispone de más de un agitador. Los tiempos de ciclo son excesivamente largos. La conformación de aleaciones de aluminio en estado semisólido es un proceso híbrido que incorpora elementos de varias técnicas clásicas de conformado. Permite libertad en el diseño del molde y en la velocidad de producción de la fundición así como una calidad metalúrgica y unas propiedades mecánicas superiores a las de la fundición en molde permanente o en fundición inyectada [1]. El interés de estas técnicas radica en la necesidad de producir nuevos componentes con menos defectos y a un coste inferior, y se fundamenta en las propiedades reológicas de los materiales cuando coexisten una fase líquida. El objetivo principal es desarrollar un procesos polivalente que permita obtener el lodo semisólido para el conformado para diferentes familias de aleaciones unas ya utilizadas y otras hasta ahora no utilizadas tanto de Al como de Mg. Esto se consigue con un diseño innovador de un agitador mecánico, con sistema de refrigeración interno mediante un fluido o gas y la incorporación de una vaina fabricada en una aleación de cobre berilio que dispone de un recubrimiento que no pueda ser disuelto por el caldo y a su vez que nos hace de aislante térmico. Todas estas mejoras hacen que el precio del prototipo sea inferior al de otros procesos ya implantados en la industria, reduciendo con este los tiempos de ciclo, minimizando el coste y la energía necesaria para la obtención del lodo. Deberemos estudiar el tipo de material del cual estará hecho, sus dimensiones y el sistema de refrigeración que tendrá para mantenerlo a la temperatura adecuada (agitador-aluminio).

The automotive industry has leaned greatly towards the use of aluminum alloys by virtue of their strength and low density. Given this, the potential for aluminum use in the fabrication of vehicle parts has greatly increased. However, there are limited studies devoted to the improvement of the casting process. In the present work, the SEED (Swirled Enthalpy Equilibrium Device) rheocasting method, as developed by Rio Tinto Alcan in collaboration with the Aluminium Technology Center of NRC Canada (ATC-NRC), was analyzed by the authors in an attempt to optimize operating parameters (e.g. proper mold filling, slurry temperature, injection speed, etc.), which affect the final cast part quality. In many of the existing semi-solid casting processes which use billets as feedstock, for example, it is often found that the outer surface of the billets is contaminated. During the injection phase, a billet's external skin comes into contact with air and lubricant, and, as a result, becomes contaminated. The use of such a contaminated billet can often result in an increased rejection rate of cast parts. The SEED process, which uses heat extraction of the liquid aluminum alloy via mechanical agitation (swirling) in a confined cylinder to form the semi-solid billet on site, has already proven successful in producing sound aluminum castings having an excellent combination of strength and ductility. The resulting semi-solid billet, having a microstructure consisting of α-Al globules surrounded by the eutectic phase, is then injected into the cold chamber of an HPDC machine., TMS 2011 Annual Meeting & Exhibition - Shape casting Symposium, San Diego, California, USA, February 27, 2011

In the last forty years, most of researches in casting fields especially in semi-solid metal state were dedicated to find new ways to enable near net shaped casting of Al alloys to improve the product properties and decreases the product cost. The thixoforming and rheocasting processes are presented as a ways by which the microstructure of the alloys can be changed to non-dendritic microstructure leading to improve the mechanical properties by mitigating the defect associated with the dendritic microstructure. Unfortunately, these processes have proved to be capital cost prohibitive and complicated for commercial production. Further, near net shaped casting of Al wrought alloys along with the superior properties and performance of these alloys have been a challenge for conventional casting routes due to the main disadvantage of hot tearing or hot cracking during solidification, which renders the cast component ineffective. To overcome the disadvantages of thixoforming and rheocasting processes, Controlled diffusion solidification (CDS) process was innovated to enable casting aluminum alloys with a non-dendritic morphology of the primary Al phase in the resultant cast microstructure and thus alleviating the problem of hot tearing and obtaining a cost effective product with improved mechanical properties. The CDS is a simple process involving mixing of two precursor alloys of different thermal masses (temperature and solute) and subsequently cast the resultant mixture of the desired solute composition and temperature as a near net shaped cast product. The process lends itself to easy commercialization with a marginal capital cost required for set up such as the addition of an extra holding furnace. Further, the CDS process would prove itself to be unique in its ability to cast Al based wrought alloys into near net shaped components without additional processes and cost.The CDS process has been proven to yield a cast product with a non-dendritic Al phase morphology and this dissertation presents the in-depth details and analysis of the various events occurring during the process to obtain a successful cast part. The process involves various inter-related events such as mixing, re-distribution of thermal field, redistribution of solute field, three types of nucleation events and growth of these different nuclei. Further the dissertation aims to present a study of the critical parameters such as temperatures of the two pre-cursor alloys, initial mass ratio of these alloys and the rate of mixing them on the effectiveness of the CDS process. The results from this study shows that mixing two precursor alloys to form the final desired alloy presents a natural environment for copious nucleation events aided by distribution of these nuclei by forced convection followed by the formation of unique cells in the resultant mixture (micro-scale) with significant thermal and solute gradients. The solidification in the CDS process is unique and different from conventional casting process in that initial growth of the nuclei takes place with the solute diffusing towards and temperature diffusing away from the solid/liquid interface which presents a favorable environment for a stable unperturbed growth of the solid/liquid interface resulting in a non-dendritic morphology of the primary AI phase.The proposed events in the CDS process has been verified with a few Al based wrought alloys and organic alloy systems. Thesis Doctor of Philosophy (PhD)

Significant progress has been made in recent years in understanding and modelling the rheology of semi-solid metals.These models show the effects of the microstructure in terms of size and morphology of globules on the material response. Morerecently it has been shown that semi-solid metals can behave as compacted granular materials such as sand. A particular signature ofsuch deformation is that the deformation becomes concentrated into shear bands which are 10−20 grains wide. Such bands have alsobeen observed in a range of cast products. Recently, it has been clearly shown that shear bands in high pressure die cast (HPDC)products are also the results of Reynolds dilatancy. Shear bands are also known to be a common feature in semi-solid metal products.The segregation banding in semi-solid metal (SSM) material and its dependence of plunger velocity were investigated. Shapedcastings were made with the RHEOMETAL™ process with a range of different plunger velocities. The microstructuralcharacteristics were investigated, with a particular emphasis on shear bands. It is shown that ingate velocities influence the locationand characteristics of the shear bands. QC 20200427

Una de las ventajas que presenta el procesado en estado semi-sólido es una baja porosidad por contracción y por gas atrapado, característica que lo hace especialmente adecuado para la fabricación de componentes con espesores variables y de mayores exigencias mecánicas. En el presente proyecto se pretende diseñar una tecnología de obtención de lingotes de Rheocasting para posteriormente ser conformados en estado semisólido, cuyo objetivo es conseguir una estructura no dendrítica mediante enfriamientos en un horno de tratamientos térmicos. Con el fin de conseguir estos resultados, se han realizado enfriamientos con diferentes rampas y posteriormente se han preparado las muestras para analizar la macro y microestructura. En este análisis se ha estudiado la estructura mediante análisis de imagen. Se ha determinado el área de fase α, la redondez de los granos, el grosor del eutéctico y la estructura globular. La aleación de aluminio estudiada es la A357. Esta aleación tiende a tener una estructura dendrítica por lo que se han tenido que usar nucleantes para ayudar a la globulización. La innovación es conseguir una estructura no dendrítica simplemente mediante enfriamientos controlados en un horno de tratamientos térmicos.

The production of alloys with rheocast structure, where the primary phase consists of globularized particles, by partial melting, involves grain recrystallization and secondary phases melting. In the process known as SIMA (Strain Induced Melt Activation), the raw material is cold deformed by a two-step rolling, making it little efficient. This work investigates the production of thixotropic material, by alternative thermomechanical treatments, of an Al-3.35wt%Cu alloy. Two treatments, which avoid the hot deformation step of SIMA, are performed: Recrystallization and Partial Melting (RAP) and Overaging (OAT) processes. In the first, the as-cast, dendritic, alloy is cold deformed at ambient temperature and then heated to a constant temperature in the mushy zone, to obtain the rheocast structure. In the second, the alloy undergoes a solution and precipitation heat treatment, before cold-deformation, with the aim of obtaining second phase precipitated particles with size and interparticle spacing favourable to the increasing of the nucleation rate of recrystallized grains, during heating of the alloy. It was found that the two routes produce globularized structures, with grain reduction of 85 % and 90 % for RAP and OAT, respectively, with respect to initial grain sizes. In general, OAT process resulted in more rounded and smaller globules than RAP.

This work is a review of the different forming and consolidation methods for particulate metal matrix composites. In the first part we focus in the forming methods from raw materials while the second is centred in the consolidation from preforms in order to get the final part. En este trabajo se ofrece una revisión de los distintos métodos de conformado y consolidación de materiales compuestos de matriz metálica reforzados con partículas. En una primera parte se hace hincapié en los métodos de conformado a partir de las materias primas y en la segunda en métodos de consolidación final a partir de preformas.

This article details research conducted to establish the optimum parameters needed to rheocast a zinc-aluminum alloy reinforced with coke-dust particles. Based on the experiments, a composite with a 10 vol. % coke-particulate reinforcement was found to exhibit good metallurgical quality (e.g., low porosity and the absence of clustering) in the final product.

Rapid slurry formation is a semi-solid metal forming technique, which is based on a so-called solid enthalpy exchange material (EEM). It is a fascinating technology offering the opportunity to manufacture net-shaped metal components of complex geometry in a single forming operation. At the same time, high mechanical properties can be achieved due to the unique microstructure and flow behaviour. The major process parameters used in the RSF process are rotation speed of the EEM, melt superheat, amount of EEM added (determining fs), and holding time. The process parameters can be well controlled with clear effects on the microstructure. There is a lack of theoretical modelling of the morphological evolution in these two-phase slurries.