Dissertations / Theses on the topic 'Aluminium High Pressure Die Casting'
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Laukli, Hans Ivar. "High Pressure Die Casting of Aluminium and Magnesium Alloys : Grain Structure and Segregation Characteristics." Doctoral thesis, Norwegian University of Science and Technology, Department of Materials Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-379.
Full textCold chamber high pressure die casting, (HPDC), is an important commercial process for the production of complex near net shape aluminium and magnesium alloy castings. The work presented in the thesis was aimed at investigating the microstructure formation in this type of casting. The solidification characteristics related to the process and the alloys control the formation of grains and defects. This again has a significant impact on the mechanical properties of the castings.
The investigations were carried out mainly using the AM60 magnesium alloy and the A356 aluminium alloy. Two different casting arrangements were used: the cold chamber HPDC and the gravity die casting methods, which allowed for different flow and solidification conditions. The microstructures in the castings were investigated using optical microscopy, image analysis, scanning electron microscopy, electron back scatter diffraction measurements and electron probe microanalysis.
In the HPDC experiments, the shot sleeve solidification conditions were investigated primarily by changing the melt superheat on pouring. This significantly affected the microstructures in the castings. The fraction of externally solidified crystals (ESCs) was consistently found to be largest near the gate in both the AM60 and the A356 die castings. This was attributed to the inherent shot sleeve solidification conditions and the flow set up by the plunger movement. When the superheat was increased, a lower fraction of ESCs was found in the castings. Furthermore, a high superheat gave ESCs with branched dendritic/elongated trunk morphology whilst a low superheat generated coarser and more globular ESCs, both in the AM60 and the A356 castings. The ESCs typically segregated towards the central region of the cross sections at further distances from the gate in the die castings.
When a thin layer of thermal insulating coating was applied on the shot sleeve wall in the production of AM60 die castings, it nearly removed all ESCs in the castings. Using an A356 alloy, (and no shot sleeve coating), with no Ti in solution gave a significantly lower fraction of ESCs, whereas AlTi5B1 grain refiner additions induced an increase in the fraction of ESCs and a significantly finer grain size in the castings. The formation of globular ESCs was enhanced when AlTi5B1 grain refiner was added to the A356 alloy.
In controlled laboratory gravity die casting experiments, typical HPDC microstructures were created by pouring semi-solid metal into a steel die: The ESCs were found to segregate/migrate to the central region during flow, until a maximum packing, (fraction of ESCs of ~35-40%), was reached. The extent of segregation is determined by the fraction of ESCs, and the die temperature affects the position of the ESCs. The segregation of ESCs was explained to occur during flow as a result of lift forces.
The formation of banded defects has also been studied: the position of the bands was affected by the die temperature and the fraction of ESCs. Based on the nature of the bands and their occurrence, a new theory on the formation of defect bands was proposed: During flow the solid distribution from the die wall consists of three regions: 1) a solid fraction gradient at the wall; 2) a low solid fraction region which carries (3) a network of ESCs. A critical fraction solid exists where the deformation rate exceeds the interdendritic flow rate. When the induced stress exceeds the network strength, deformation can occur by slip, followed by liquid flow. The liquid flow is caused by solidification shrinkage, hydrostatic pressure on the interior ESC network, and gaps forming which draw in liquid.
Roberts, Michael John, and edu au jillj@deakin edu au mikewood@deakin edu au wildol@deakin edu au kimg@deakin. "A Modified Life Cycle Inventory of Aluminium Die Casting." Deakin University. School of Engineering and Technology, 2003. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20040825.110759.
Full textSivertsen, Halses Sebastian. "Die life prediction using High Pressure Die Casting simulations." Thesis, Tekniska Högskolan, Jönköping University, JTH, Material och tillverkning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-50031.
Full textWatson, Douglas. "Microstructure and mechanical properties of ductile die-cast Al-Mg-Si-Mn alloys." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/12874.
Full textPereira, M. F. V. T., M. Williams, and Preez W. B. Du. "Characterization of metal powder based rapid prototyping components with respect to aluminium high pressure die casting process conditions." Journal for New Generation Sciences, Vol 8, Issue 2: Central University of Technology, Free State, Bloemfontein, 2010. http://hdl.handle.net/11462/563.
Full textThis paper is based on tests performed on die component specimens manufactured by EOS-DMLS (direct metal laser sintering) and LENS (laser engineered net shape) RP (rapid prototyping) technology platforms, as well as manufactured specimens machined out of preferred standard hot work steel DIN 1.2344. These specimens resemble typical components used in metal high pressure die casting tool sets. The specimens were subjected to a programme of cyclic immersion in molten aluminium alloy and cooling in water-based die release medium. The heat checking and soldering phenomena were analyzed through periodic inspections, monitoring crack formation and evidence of surface washout. At the end of the thermal tests, mechanical strength and hardness tests were performed to assess toughness and core resistance variations in relation to the initial conditions. Finally metallographic investigations were performed through optical microscopy on all the specimens considered. The outcomes of this research will be presented and used by the CSIR for further development and application of the assessed EOS-DMLS and LENS rapid prototyping technologies in rapid die manufacturing techniques and die design principles, including time and economic feasibility criteria to be applied when considering rapid die manufacture.
Pereira, Manuel Filipe Viana Teotonio. "ADDITIVE MANUFACTURING OF COMPONENTS FOR IN-DIE CAVITY USE, SUITABLE TO WITHSTAND ALUMINIUM HIGH PRESSURE DIE CASTING (HPDC) PROCESS CONDITIONS." Thesis, Bloemfontein: Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/243.
Full textThis research examines the suitability of Additive Manufacturing (AM) for manufacturing dies used in aluminium high pressure die casting. The study was guided by the following objectives: • The reviews of applicable literature sources that outline technical and application aspects of AM in plastic injection moulds and the possibilities of applying it to high pressure casting die. • To introduce AM grown die components in die manufacture. Further, to develop a methodology that will allow industry to apply AM technology to die manufacture. • Revolutionise the way die manufacture is done. The potential for AM technologies is to deliver faster die manufacture turnaround time by requiring a drastically reduced amount of high level machining accuracy. It also reduces the number of complex mechanical material removal operations. Fewer critical steps required by suitable AM technology platforms able to grow fully dense metal components on die casting tools able to produce production runs. • Furthermore, promising competitive advantages are anticipated on savings to be attained on the casting processing side. AM technology allows incorporation of features in a die cavity not possible to machine with current machining approaches and technology. One such example is conformal cooling or heating of die cavities. This approach was successfully used in plastic injection mould cavities resulting in savings on both the part quality as well as the reduction on cycle time required to produce it (LaserCUSING®, 2007). AM technology has evolved to a point where as a medium for fast creation of an object, it has surpassed traditional manufacturing processes allowing for rapidly bridging the gap between ideas to part in hand. The suitability of the AM approach in accelerating the die manufacturing process sometime in the near future cannot be dismissed or ignored. The research showed that there is promise for application of the technology in the not too distant future. In the South African context, the current number and affordability of suitable AM platforms is one of the main stumbling blocks in effecting more widespread applied research aimed at introduction of the technology to die manufacture.
Binney, Matthew N. "Porosity reduction in high pressure die casting through the use of squeeze pins /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19810.pdf.
Full textMíšek, Jakub. "Vliv odplynění na kvalitu odlitků vyrobených technologií vysokotlakého lití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318844.
Full textKnoll, Octavian [Verfasser], Karl [Mitwirkender] Schweizerhof, and O. S. [Akademischer Betreuer] Hoppenstad. "A Probabilistic Approach in Failure Modelling of Aluminium High Pressure Die-Castings / Octavian Knoll. Betreuer: Karl Schweizerhof ; O. S. Hoppenstad." Karlsruhe : KIT-Bibliothek, 2015. http://d-nb.info/1081213019/34.
Full textKlarner, Andrew Daniel. "Development of Mg-Al-Sn and Mg-Al-Sn-Si Alloys and Optimization of Super Vacuum Die Casting Process for Lightweight Applications." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515083355012541.
Full textJankes, Erik. "Využití řízeného naplyňování slitin Al-Si při tlakovém lití." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231052.
Full textAfsaridis, Kimon. "Investigation of residual stresses generation in aluminum flywheel." Thesis, Jönköping University, Jönköping University, JTH. Research area Product Development, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-9255.
Full textQuality of the castings is affected by several factors which the designer should take into consideration during the product development process. Although residual stress is one of those, it is often not considered in practical computations. Hence residual stresses are one of the forgotten areas in designing of machine parts. This master thesis is focused on the investigation of residual stresses in a high pressure die casted component, with the aim of extending its service life, by taking results from the study as a feedback.
The investigation of residual stresses was done on a variety of specimens, cast aluminum flywheel, provided by Husqvarna AB. This flywheel is a component in a product of the same company.In evaluating the residual stresses in the part, two tools-simulation and physical measurement were used. Moreover, comparison with these two methods is also done at an area of interest on the flywheel. The simulation was carried out by using MAGMAhpdc-a module for high pressure die casting process, from the commercial software package MAGMAsoft; while for the physical measurements, the hole drilling method was used, a method believed to be less accurate at low stresses areas.
The findings obtained from this study show that the results from both procedures are close, with small deviations observed, which reveals the reliability of the hole drilling method even when the stress levels are low. It is also found that the compressive residual stresses dominate in the component-a preferred phenomenon with regards to residual stress.
Chintalapati, Pavan. "Solidification under pressure of aluminum castings." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2010r/chintalapati.pdf.
Full textTitle from PDF t.p. (viewed June 30, 2010). Additional advisors: Viola L. Acoff, Krishan K. Chawla, Raymond J. Donahue, Gregg M. Janowski, Harry E. Littleton (ad hoc). Includes bibliographical references (p. 143-138).
Hamasaiid, Anwar. "Transferts thermiques interfaciaux en fonderie en moules métalliques d'alliages légers." Toulouse 3, 2007. http://www.theses.fr/2007TOU30249.
Full textThe present investigation is about the interfacial heat transfer during the solidification of light alloys in Gravity (GDC) and High Pressure (HPDC) Die Casting processes. The study consists of three principle fields, experimental, analytical and modelling. The Experimental activity involves measuring the temperature around the casting-die interface, in the mould and at the surface of the castings and other process parameters during die filling and solidification. For this purpose, suitable experimental methods and sensors have been developed. Particularly a pyrometric measurement method has been adapted to measure the casting surface temperature during its solidification. Hundredths of trials were performed using Al-7Si-0. 3Mg, A-9Si-3Cu and AZ91 D alloys during the two investigated processes. From the temperature measurements, interfacial heat transfer coefficient and heat flux density have been evaluated using an inverse method. The obtained results have been analysed with regards to the various process parameters and to the microstructure of the castings. .
Vicario, Gomez Iban. "Influence des nano-particules d’alumine (Al2O3) et de di-borure de titane (TiB2) sur la microstructure et les propriétés de l’alliage Al-Si9-Cu3-Fe1 pour des applications de fonderie à haute pression." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14420/document.
Full textThe work has been focused on the study of the influence of TiB2 and Al2O3 nano-particles (up to 1 wt. %) on the properties and physical features of an aluminium casting alloy, Al-Si9Cu3Fe1.Samples have been obtained through the High Pressure Die Casting (HPDC) process and compared with unreinforced samples obtained at the same conditions. It has been observed that the Al2O3 and TiB2 particles have a direct influence on several features of the alloy such as the microstructure and precipitating phases as well as in the improvement of the soundness and mechanical and electrical properties. Al2O3 and TiB2 particles can be used to tailor the properties of the alloy and to match the specifications of light weight applications
Tavakoli, Shahab. "Modélisation du cycle thermique des moules de fonderie sous pression." Thesis, Paris 10, 2014. http://www.theses.fr/2014PA100095.
Full textReducing the weight of vehicles, specially the powertrain Group, contributes to the reduction of the emissions. Today, in order to achieve this objective, the automobile parts conception (Housing gear box, Cylinder block) in lightweight materials such as aluminum and its alloys is increasing. For the mass production, aluminum alloys are formed by a foundry process called ‘’High Pressure Die Casting’’.This process uses the metal molds. Control the thermal behavior of the mold : Heating, intern cooling (by circuit) and extern cooling, is a key point to ensure castings quality and rate of production.In this thesis, the industrial process has been detailed since the mold closing and aluminum melting injection in the die, to the mold opening time and the part (Gearbox RENAULT) ejection. Then, the mold design details, different generation of the cooling systems and the parameters of each step of the manufacturing process taking into account the actual cooling system are presented. The actual cooling systems in the dies are positioned today in empirical way. The ultimate goal of this thesis is to provide the key elements for the cooling system conception from the thermal behavior point of view. For this one, a complete modeling of the phenomena has been realized and validated by 8 thermocouples and the cooling system position has been defined from the thermal equations. The thermal cycle of the die has been optimized and allowed us to reduce and homogenize the temperature fields on the die surface during the production. The rate of production, the castings quality and the lifetime of the die have been consequently increased
Butler, Simon Andrew. "The development of a reliable high strength aluminium casting alloy." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570853.
Full textLong, A. D. "Extending life of High Pressure Die Casting Dies." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527834.
Full textSadeghi, Mohammad. "Optimization product parts in high pressure die casting process." Licentiate thesis, Mälardalens högskola, Framtidens energi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-27733.
Full textElfakharany, Essameldin F. "Qualitative Reasoning for filling pattern in high-pressure die-casting and gravity-driven casting /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488192447430967.
Full textGraziani, Alessandro. "Chemical composition modification of casting aluminium alloys for engine applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10018/.
Full textYan, Feng. "Development of high strength Al-Mg2Si-Mg based alloy for high pressure diecasting process." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/13883.
Full textCarbin, R. "Factors affecting the production of aluminium alloy automotive wheels by the low pressure die casting process." Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636205.
Full textSpataro, Mark Paul. "Comparison of mechanical performance between magnesium alloy sand castings and high pressure die castings /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18378.pdf.
Full textClinch, Michael. "The thermomechanical processing of aluminium alloys for high pressure gas cylinders." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326551.
Full textTang, Caixian. "Soldering in magnesium high pressure die casting and its preservation by surface engineering." Swinburne Research Bank, 2007. http://hdl.handle.net/1959.3/22747.
Full text[A thesis submitted] for the degree of Doctor of Philosophy, Industrial Research Institute, Swinburne University of Technology - 2007. Typescript. Includes bibliographical references (p. 154-167).
Fraser, Darren T. "Soldering in high pressure die casting and its prevention by lubricant and oxide layers /." [St. Lucia, Qld.], 2000. http://adt.library.uq.edu.au/public/adt-QU20010830.163828/.
Full textYang, Xinliang. "Particle dispersion in aluminium and magnesium alloys." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14437.
Full textGulizia, Stefan. "Soldering in high pressure die casting (HPDC) performance evaluation and characterisation of physical vapour deposition (PVD) coatings /." Swinburne Research Bank, 2008. http://hdl.handle.net/1959.3/39640.
Full textThesis submitted for the degree of Master of Engineering, School of Engineering and Science, Swinburne University of Technology, 2008. Typescript. Includes bibliographical references (p. 98-101).
Newell, Matthew David. "Aspects of a novel casting process for the production of nickel-based superalloy high pressure turbine blades." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/525/.
Full textSchaub, Henning. "Comparison of different aluminium casting processes from an environmental perspective : Case study on plaster mould castings produced in Mid Sweden." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35659.
Full text2018-10-10
Watson, Robert. "New numerical techniques to quantify and predict the effect of entrainment defects, applied to high pressure die casting." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7153/.
Full textLaw, Madeleine. "Investigations on the Formation of Defect Bands in Semi-Solid High Pressure Die Cast Aluminium-Silicon Alloys." Licentiate thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-272086.
Full textProduktion av högtrycksgjutning av halvfasta aluminium-kisellegeringar används i fordonsindustrin för att tillverka komponenter, som exempel till kåpor, konsoler och stag. Det är allmänt känt att defektband kan formas under högtrycksgjutning som följer konturen av komponentytan. Dessa band består huvudsakligen av eutektisk fas. Detta fenomen har också observerats vid högtrycksgjutning produktion av halvfast slurry. Potentiellt kan dessa band leda till en försämring av komponentens mekaniska egenskaper och resultera i ett förtida brott. Ursprunget av dessa band är inte helt kartlagda och det är därför viktigt att fokusera ytterligare på denna forskning och att undersöka dessa band och deras ursprung. En serie med gjutningsförsök genomfördes med varierande kolvhastighet. Efterföljande undersökning med optisk- och svepelektronmikroskopi visade att en förändring av kolvhastigheten förändrar antalet band som finns i proverna. Energidispersiv röntgenspektroskopi avslöjade en mätbar skillnad i aluminiumkvantitet över bandet, och det antogs att aluminium migrerar mot centrum av komponenten. Därför undersöktes och utvärderades olika mekanismer som ansvarar för partikelmigrationer som finns att finna i litteratur med hjälp av experimentella data och information från publicerad litteratur. Det visade sig att Saffman lyftkraft och Mukai-Lin-Laplace effekten var de mekanismer som mest troligen orsakade migration av aluminium. Ytterligare experimentella försök rekommenderas för att identifiera vilken av dessa två mekanismerna som i slutändan är ansvarig för migrationen. Detta för att optimera gjutningsprocessen och därmed minimera uppkomsten av defektband.
Okcu, Isik Yilmaz. "Effect Of Process Parameters On Mechanical Properties Of High Pressure Die Cast Magnesium Az91 Components." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613896/index.pdf.
Full textPereira, M. F. V. T., M. Williams, and R. Bruwer. "Rapid die manufacturing using direct laser metal deposition." Journal for New Generation Sciences, Vol 7, Issue 3: Central University of Technology, Free State, Bloemfontein, 2009. http://hdl.handle.net/11462/542.
Full textGlobal issues such as energy and climate changes have impacted on both the automotive and aerospace industries, forcing them to adopt measures to produce products that consume fewer combustibles and emit less carbon dioxide. Making vehicles lighter is one of the logical ways of reducing fuel consumption. The need for light components, able to fulfil technical and quality specifications, led to market growth for tooling that is able to mass produce parts using manufacturing processes such as high pressure die casting. Competitive pressures to reduce the lead time required for tooling-up has also increased dramatically. For this reason research into various methods, techniques and approaches to tool manufacture is being undertaken globally. This paper highlights the work undertaken at the CSIR on the issue of rapid die manufacturing through the application and evaluation of a rapid prototyping technique and coating technologies applied to die components of a high pressure casting die for the production of aluminium components. Criteria for determining suitability were developed against which the technique was evaluated that included time, cost and life-expectancy. Results of accelerated testing procedures to evaluate the die material produced by the rapid prototyping technique and surface coatings and treatments of die materials for their resistance to washout, erosion, heat checking and corrosion in a high pressure die casting environment, are presented. The outcomes of this research will be used for further development and application of specific techniques, design principles and criteria for this approach.
Štipl, Pavel. "Technologie lití vysokotlakých odlitků a vlivy působící na jejich kvalitu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231432.
Full textDočekal, Václav. "Vady tlakově litých odlitků ze slitin hliníku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401515.
Full textSvoboda, Rostislav. "Tlakově lité odlitky z Mg slitin - trendy vývoje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228049.
Full textOutmani, Imane. "Caractérisation des variabilités Matériaux/ Process pour une convergence produit de fonderie par approche prédictive." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0007/document.
Full textSecondary Al-Si alloys are widely used in automotive industry for engine blocks because they offer a considerable weight reduction whilst maintaining good mechanical properties. The ever-expanding internationalisation of production, with same stages of production processes spread across a number of countries to produce locally, causes however high variability in the casting products. The chemical composition of the same alloys and the working variables of the unchanged high-pressure die casting process (HPDC) may change for the same casting parts from one country to another, they can even sometimes vary from one manufacturing site to another within the same country. Designing for aluminium automotive components does call today for new deterministic design methods that are often achieved from European material and casting process databases, which can affect the properties of these parts in the case of a location outside Europe. Thus, it is important to adapt the design of die casting parts quickly and inexpensively by taking into account the material and process local constraints. In this work, a methodological approach which permits to predict mechanical properties as a function of material and process variability based on an experimental/ statistical study on the effect of the variability of the primary factors of alloying elements contents (Si, Cu and Mg) and HPDC process parameters (casting temperature and injection pressure) on mechanical properties of die cast aluminium alloys has been proposed. The microstructural features and the porosity level were also investigated and assessed. This approach has resulted in statistical design tool that will allow designers to make changes to the design of their casting and to industrialize them outside Europe
Tharayil, Pradeep Ambareeksh, and Mohammadali Baradaran. "HPDC Die design for Additive Manufacturing : Simulation and Comparison of Thermal Stresses in HPDC die designed for Additive Manufacture." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Industriell produktutveckling, produktion och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-43319.
Full textDézécot, Sébastien. "Caractérisation et modélisation du rôle des défauts microstructuraux dans la fatigue oligocyclique des alliages d'aluminium de fonderie : Application au procédé à modèle perdu." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI148/document.
Full textThis study aims to characterize the fatigue damage mechanisms that lead to the rupture of a cast aluminum alloy AlSi7Cu3Mg produced by lost foam casting at 250°C under large scale yielding. Its characterization by X-ray micro-tomography (µCT) showed the complexity and the strong 3D aspect of its microstructure: large pores with complex shapes (>1mm) and a network of interconnected hard particles are present. An experimental setup was developed to perform high-temperature fatigue tests monitored in situ by synchrotron µCT. These tests revealed the interactions between cracks and microstructural elements. Cracks initiated, in the bulk, on hard particles located in the vicinity of shrinkage cavities. Cracks propagation appears to be correlated to the progressive rupture of particles present in front of the crack tip. These observations were completed by crack growth tests carried out on macroscopic specimens. A pore-free material (similar to the first) was produced to dissociate the role of pores and particles on the low cycle fatigue behavior of the material. Pores appear to be more critical regarding cracks initiation. Realistic finite element meshes have been generated to perform elasto-viscoplastic simulations which have allowed to propose a criterion for cracks initiation. Critical areas regarding cracks initiation are correlated to areas where the inelastic strain energies are maximum. The crack paths correspond to areas where inelastic strains are located and where the levels of stress triaxiality are high. All these informations allowed to propose a damage scenario. Finally, the tests on macroscopic specimens allowed to propose a crack growth speed model for both materials. This model, easily usable by engineers, have been validated for different loadings
Schremmer, Michael. "Potentialanalyse zur Verwendung des Leichtmetalls Magnesium im Fahrwerk eines Automobils." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2013. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-118583.
Full textBlombäck, Oscar, and Marcus Dahlén. "Minimering av porositet vid vakuumassisterad kallkammarpressgjutning av Al-Si : En fallstudie enligt DMAIC på Husqvarna Group." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85097.
Full textPressure die casted Al-Si components are increasingly found inside internal combustion engines, resulting in weight reduction and increased durability. Characteristic to die casting, commonly associated with cost-effective mass production, is the formation of pores which, if unnoticed, can cause leakage, structural deficiencies, and thus reduced durability and life-length of components. Pores commonly appear internally, making identification of faulty components difficult. Therefore, finding parameter settings in the die casting process that consistently minimizes the formation of pores is of importance. A company struggling with porosity-related defects is Husqvarna Group, currently using vacuum-assisted die casting to produce engine cylinders of Al-Si. Scrap-rate, specifically related to porosity, of a particular cylinder model has doubled in the last three years, causing waste of both precious production time and higher quality deficiency costs. A vacuum-assisted die casting process consists of several steps: (1) liquid Al-Si is poured into a cylindrical shot sleeve, (2) a plunger is moved towards a small gate, leading to the die cavity, at low velocity as to not cause turbulence, whilst vacuum is applied throughout the cavity and shot sleeve, (3) plunger velocity is increased substantially at a predetermined switch point, resulting in a spray-filling of the die cavity, and (4) high pressure is applied to continue the feed of molten metal into the cavity as solidification occurs. The purpose of the thesis has been to investigate if and how various parameters, related to the aforementioned four steps of the die casting process, impact the porosity amount in an industrial product. The acquired process knowledge was then applied to identify parameters affecting porosity and recommend settings that consistently minimize the porosity amount. The experimental procedure consisted of two steps: firstly, a screening experiment of six process parameters was made by simulating the die casting process according to a fractional factorial design. Secondly, a real-world experiment was conducted following a central-composite design by varying the three most impactful parameters from the screening experiment. Analysis of the experiments resulted in a selection of parameter settings, anticipated to reduce porosity by over 70%. A lower porosity amount will most likely reduce the scrap rate of the cylinder model, resulting in substantial savings and higher production efficiency. For practitioners, the main contribution of this thesis is a method of systematic quality-improvement to die-casted components by a combination of simulation experiments and real-world tests.
Milhem, Luc. "Fonderie sous pression du cuivre : étude du procédé et caractérisation du matériau." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR14.
Full textThis research focuses on the study of high pressure die casting (HPDC) of copper. In order to improve the properties of die-cast copper, two main issues were investigated. In the first part, attention is paid to the influence of melting parameters and of addition of alloying elements in small amounts on the characteristics of the specimen produced. The second part discusses the influence of the foundry process itself on properties of die cast part, in particular by studying two parameters : the metal flow type during cavity filling, and the air entrapment
Koplík, Jiří. "Snížení nákladů na výrobu odlitku litého tlakovým litím pomocí aplikace vysokoteplotního separátoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318779.
Full textKeller, Kevin. "Schockwellensynthese und Charakterisierung von Aluminiumnitrid mit Kochsalzstruktur." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-131930.
Full textIn the present work the results of the synthesis and characterisation of the high-pressure phase of aluminium nitride with rocksalt structure (rs-AlN) are presented. The experiments were carried out with the flyer-plate-method with subsequently sample recovery. For different aluminium nitride powders with starting porosities k = rho_solid/rho_porous of 1.5 to 2.5 the phase transition from wurtzite structure (w-AlN) to the rocksalt structure (rs-AlN) was induced at a pressure of 15 to 43 GPa. This is to our knowledge the first succesful synthesis of rs-AlN with dynamic HP-HT methods. With this advance, samples in the milligram or gram range can be produced. Therefore further investigations to characterise the material are possible, especially the study of the mechanical, thermal and chemical stability to validate the potential for the production of ultrahard composites. The shocked samples consist of a phase mixture from the starting material (w-AlN), the high-pressure phase (rs-AlN), aluminium oxide and oxynitrides, as well as amorphous aluminium hydroxides. The highest yield of rs-AlN (~41 wt% at 2 mm sample height) can be obtained at a pressure of 24 GPa and a starting porosity k of 2.1. The shock temperature can be estimated by the formation of different Al-O-N phases (<1700 °C to <2000 °C). The phase transition is activated by the raise of temperature due to shock compression. A thermal activated reconversion to the low-pressure phase w-AlN caused by a high post-shock temperature and a slow cooling of the sample is postulated as a contrary process. This results in an optimum temperature of 1700 to 1900 °C for this set-up. A decrease of the sample height increases the influence of multiple reflections and therefore causes a better transformation. A partial conversion to rs-AlN was observed for three nanopowders (crystallite size <25 nm), whereas for a more coarse nanopowder and an submicronpowder (crystallite size >45 nm) no rs-AlN could be found in the shocked samples. A stabilisation mechanism of the rocksalt phase by crystallite size effects is predicted. The reduction of the crystallite size causes a decrease of the transition pressure for w-AlN -> rs-AlN. It can be concluded, that for smaller particles the high-pressure phase can be stabilised at ambient conditions on the basis of the smaller distance from equilibrium, whereas for larger particles the reconversion to the low-pressure phase occurs. By a Rietveld refinement of the X-ray diffractograms, the lattice constant of rs-AlN and the crystallite size was determined to be a = 4.044 ± 0.001 Å respectively 15.3 ± 0.2 nm. The crystallite size of rs-AlN (10 to 20 nm) determined with high-resolution transmission electron microscopy (TEM) is in good agreement with the results of the Rietveld refinement. The octahedral Al–Npolyhedral (AlN6) was demonstrated by 27Al nuclear magnetic resonance spectroscopy (NMR) with a corrected chemical shift of 2 ppm. Based on infrared spectroscopy (FTIR) an AlN vibration band at about 490 cm−1 is assumed. Dynamic thermal analysis show, that the rs-AlN starts to oxidise to alumina at 600 °C and thus have no greater resistance in comparison with w-AlN. The thermal activated reconversion of rs-AlN to the low-pressure phase starts at 1200 °C (in argon) respectively 1100 °C (under vacuum) at a heating rate of 10 K/min. The aluminium nitride with rocksalt structure shows a good chemical resistance against water, caustic soda and acids (HCl, H2SO4, H3PO4, HNO3 and aqua regia)
Maurer, Simon Alexander. "Multidisziplinäre Formoptimierung modularer Grundgeometrien für Druckgussbauteile mit strömungs- und strukturmechanischen Zielfunktionen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-197331.
Full textThe virtual development process of an automotive casting part usually begins with classical design tasks and analyses of material strength, stiffness and crash load cases. In the next step, often in cooperation with external suppliers, the tooling concept is developed and casting simulations are used to ensure manufacturability. During manufacturing there is a scatter in process parameters, such as flow velocity or temperature levels, which in turn cause a scatter in the performance of the final product (e.g. local elongation at fracture or ultimate tensile strength). Means to increase process stability and yield are often limited to knowledge-based improvements of the manufacturing process parameters and adaptations of the gating and overflow system. Major changes to the part geometry are usually no longer possible due to project time constraints. Therefore it is the goal of this thesis to optimize modularized basic geometries, like ribs or bends, by using numerical shape optimizations and employ them right from the beginning of the part development process. For the objective functions of the optimizations the disciplines of fluid dynamic filling and the resulting structural behaviour are considered. In addition, the resulting shape is analyzed with regards to robustness towards scatter in manufacturing operating conditions. By using these new modularized geometries the overall robustness of the final product is expected to be increased
Dini, Hoda. "As-cast AZ91D magnesium alloy properties : Effects of microstructure and temperature." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Material och tillverkning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-38148.
Full textNumera finns det ett väsentligt behov av lätta, energieffektiva och miljövänliga tekniksystem. Detta behov är drivkraften för utveckling av ett brett utbud av material för energigenerering, energilagring, framdrivning och transport. Dessa utmaningar motiverade användningen av magnesiumlegeringar för lättviktskonstruktioner. Magnesium har en densitet på 1,74 g/cm3, vilket är ca 30% lägre än för aluminium, en fjärdedel av densiteten för stål och nästan i nivå med många polymerer. Då magnesiumlegeringar dessutom är lätta att återvinna, jämfört med polymerer, gör det dem miljömässigt attraktiva. Låga mekaniska egenskaper är den främsta orsaken till begränsad användning av dessa legeringar för lastbärande tillämpningar. Mg-Al-Zn-legeringen AZ91D uppvisar en utmärkt kombination av styrka, gjutbarhet och korrosionsbeständighet. Dess mekaniska egenskaper vid förhöjd temperatur, som tex kryphållfasthet, är låga. Dessutom är korrelationen mellan mikrostruktur och mekaniska egenskaper oklar. Denna avhandling syftade till att ge ny kunskap om mikrostrukturens roll för magnesiumlegeringars mekaniska egenskaper. Slutligen var materialets egenskaper i förhållande till processparametrar vid tillverkningen av stort intresse. En omfattande karaktärisering av kornstorleks-, sekundära dendritarmavstånds (SDAS)-fördelning och fraktion av Mg17Al12 utfördes med hjälp av optisk mikroskopering och diffraktion av bakåtspridda elektroner (EBSD). Mikrostrukturen korrelerades till sträckgränsen (Rp0.2), brottstyrkan och brottförlängningen. Det föreslogs att den intermetalliska fasen, Mg17Al12, spelar en viktig roll vid bestämning av legeringens mekaniska och fysikaliska egenskaper vid temperaturintervall från rumstemperatur upp till 190°C genom att bilda ett styvt nätverk av intermetaller. Uppkomsten av ett sådant nätverk stöddes genom en studie av den termiska expansionen av legeringen för olika fraktioner av Mg17Al12. En fysikalisk konstitutiv modell med ett brett giltighetsområde användes framgångsrikt för att beskriva det plastiska flytbeteendet hos AZ91D för olika mikrostrukturer. De temperaturberoende variablerna i modellen korrelerade ganska väl med materialets underliggande fysik. Modellen validerades genom att jämföra dislokationstätheten som predikterades av modellen och den med EBSD uppmätta dislokationstätheten. Påverkan av pressgjutningsparametrar på geometrisk tolerans och restspänning hos de gjutna komponenterna studerades. Vidare studerades geometrisk tolerans och restspänning av komponenter efter pening och målning. Intressant nog hade eftermatningsfasen en stor effekt på geometrisk tolerans och restspänningar. Dessutom hade temperaturen på den fasta formhalvan av verktyget även ett visst inflytande på komponentens geometriska tolerans och restspänning.
Griveau, Jean-Christophe. "Etude de composés fermions lourds supraconducteurs sous hautes pressions : CECU2SI2 et UPD2AL3." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10252.
Full text(9721637), Carl Kuang Yu Shi. "Electric Infrared Die heating for Aluminum High Pressure Die Casting." Thesis, 2020.
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