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Stereometry specification and properties of anodization surface of casting aluminium alloys  [PDF]
J. Konieczny,K. Labisz,J. Wieczorek,L.A. Dobrzański
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties, thickness and structure of an anodic layer formed on aluminium casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT, abrasive wear test was made with using ABR-8251 equipment delivered by TCD Teknologi ApS and microstructure investigations were made with using a light microscope equipped with an electronic camera configured with a computer on two casting aluminium alloys which both were founding by pressure die casting and gravity casting.Findings: The researches included analyze of the influence of chemical composition, geometry, roughness and abrasive wear resistant of anodic layer obtained on aluminium casts.Research limitations/implications: Contributes to research on anodic layer for aluminium casting alloys.Practical implications: Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminium casting alloys, e.g. in the range of raising resistance on corrosion.Originality/value: The range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.


金属学报(英文版) , 2003,
Abstract: A new method (liquidus casting) was used for 356 Al alloy semi-solid slurry mak-ing. The structures of 356 Al alloy cast by a Fe mould and semi-continuous castingmachine at different temperatures were investigated. How the globular grains formwas also discussed. The results show that either being cast by single Fe mould orsemi-continuous machine, the microstructures are not conventional dendrites but fineand net-globular grains. The average grain size is smaller than 30μm and suitableenough for thixoforming, meanwhile it can improve the mechanical properties of fol-lowing products. Under the suitable casting velocity and cooling intensity, most ofglobal grains prolong their global growth and collide with each other before dendriticgrowth because of the large amount of the nucleation sites.
Multiple defect distributions on weibull statistical analysis of fatigue life of cast aluminium alloys
C Nyahumwa
African Journal of Science and Technology , 2005,
Abstract: From an engineering point of view, the fatigue strength variability of cast aluminium alloy components requires a detailed understanding of the inconsistency of cast defect distribution. Cast aluminium alloys are not generally homogeneous; they may contain two or more types of common casting defects, which are gas and shrinkage porosities, oxide films, and inclusions. Each defect type has its own distribution of sizes; and multiple cast components of presumably the same material may have different histories and therefore different cast defect populations. A number of statistical analyses of fatigue data assume that a single distribution of casting defect is present uniformly throughout the cast aluminium alloys. As a result, fatigue data are statistically not correctly described. By relaxing the assumptions of a single cast defect distribution, of uniformity throughout the material and of uniformity from specimen to specimen, Weibull statistical analysis for multiple defect distributions have been applied to correctly describe the fatigue life data of aluminium alloy castings having multiple cast defects competing to initiate fatigue cracks.
Permeability of Aluminium Foams Produced by Replication Casting  [PDF]
Eugeny L. Furman,Arcady B. Finkelstein,Maxim L. Cherny
Metals , 2013, DOI: 10.3390/met3010049
Abstract: The replication casting process is used for manufacturing open-pore aluminum foams with advanced performances, such as stability and repeatability of foam structure with porosity over 60%. A simple foam structure model based on the interaction between sodium chloride solid particles poorly wetted by melted aluminum, which leads to the formation of air pockets (or “air collars”), is proposed for the permeability of porous material. The equation for the minimum pore radius of replicated aluminum foam is derived. According to the proposed model, the main assumption of the permeability model consists in a concentration of flow resistance in a circular aperture of radius r min. The permeability of aluminum open-pore foams is measured using transformer oil as the fluid, changing the fractions of initial sodium chloride. Measured values of minimum pore size are close to theoretically predicted ones regardless of the particle shape. The expression for the permeability of replicated aluminum foam derived on the basis of the “bottleneck” model of porous media agrees well with the experimental data. The obtained data can be applied for commercial filter cells and pneumatic silencers.
Effects of Cooling Media on the Mechanical Properties and Microstructure of Sand and Die Casting Aluminium Alloys
BO Adewuyi, JA Omotoyinbo
Journal of Science and Technology (Ghana) , 2008,
Abstract: Die and sand castings are versatile processes capable of being used in mass production of alloys having properties unobtainable by other manufacturing method. In this research, efforts were made to study the effects of cooling media on Aluminium alloy cast. Aluminium scrap (Al – Mg – Si,) were charged into crucible furnace from which as-cast aluminium samples for the experimental work were obtained. The specimens were subjected to hardness test, tensile test and metallographic examination. The results show that samples obtained from air cooled dies had the best mechanical properties and those produce by sand casting had comparable hardness values but lower tensile properties. Other results show that the hardness of cast alloys can be varied by changing the cooling media.
Numerical microstructure prediction for an aluminium casting and its experimental validation  [PDF]
Unterreiter Guenter,Ludwig Andreas,Wu Menghuai
China Foundry , 2011,
Abstract: Virtual manufacturing based on through-process modelling becomes an evolving research area which aims at integrating diverse simulation tools to realize computer-aided design, analysis, prototyping and manufacturing. Numerical prediction of the as-cast microstructure is an initial and critical step in the whole through-process modelling chain for engineering components. A commercial software package with the capability of calculating important microstructure features for aluminium alloys is used to simulate a G-AlSi7MgCu0.5 laboratory casting. The simulated microstructure, namely grain size, secondary dendrite arm spacing and diverse phase fractions are verified experimentally. Correspondence and discrepancies are reported and discussed.
Experimental Study of Correlation of Mechanical Properties of Al-Si Casts Produced by Pressure Die Casting with Si/Fe/Mn Content and Their Mutual Mass Relations  [PDF]
Marcel Fedak,Miroslav Rimar,Ivan Corny,Stefan Kuna
Advances in Materials Science and Engineering , 2013, DOI: 10.1155/2013/585714
Abstract: The submitted contribution addresses problems concerning influence of alloying elements (Si/Fe/Mn) of Al-Si pressure die casts (HPDC) on values of residual deformation. On the basis of results of executed experiments, mutual correlations are analyzed and described, while not only measurements results are evaluated but also metallographic outputs of obtained compounds from the view of their formation, occurrence, and size. The development of intermetallic phases structures Al(FeMn)Si as well as intermetallic ferritic phase Al3FeSi was observed. More verification experiments follow in order to apply obtained knowledge for improvement and/or preservation of casts properties on required level. 1. Introduction Parts manufactured by pressure die casting distinguish by suitable properties in relation to their mass. In present, these products/casts are utilized in various spheres of industries, significant share of which is automotive industry [1]. An important requirement in this sphere is resultant mass of products, whilst all claimed properties are preserved. The trend of mass reduction leads to application of aluminium-based materials, while demands on strength, extensibility, and other mechanical properties are on the same level as for Fe-based materials. The paper describes basic impacts of chosen alloying elements on permanent deformation as a significant mechanical property. Mutual correlations between chosen alloying metals and resulting deformation measured on a group of casts are described. Consecutively these relations are observed during variation of content of the alloying elements in order to increase resulting strength of the cast. Providing stability in casting process is of great importance, since it has direct impact on resulting cast properties [2–4]. Aluminium alloys are die cast under pressure on casting machines with cold chamber [5, 6]. Significant factor of the process is corrosive effect of liquid aluminium alloys particularly at higher temperatures, this effect makes it impossible to employ casting machines with hot chamber [6–8]. Horizontal cold chambers are relatively simple, and it is possible to apply higher specific pressure on the cast metal. Thus, it is possible to cast light-walled casts with smooth surface and high mechanical properties. These advantages of horizontal chamber make it possible to design large casting machines with voluminous loading chamber and closing force up to 30?MN, with gross cast mass 30?kg or more, in casting of aluminium alloys (charge utilization of 80%) [6, 9, 10]. The quality of aluminium casts
Intermetallic phase particles in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys  [PDF]
G. Mrówka-Nowotnik
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: In the technical Al alloys even small quantity of impurities - Fe and Mn - causes the formation of new phase components. Intermetallic particles form either on solidification or whilst the alloy is at a relatively high temperature in the solid state, e.g. during homogenization, solution treatment or recrystallization. The exact composition of the alloy and casting condition will directly influence the selection and volume fraction of intermetallic phases. The main objective of this study was to analyze the morphology and composition of complex microstructure of intermetallic phases in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy (LM), scanning (SEM) electron microscopy in combination with X-ray analysis (EDS) using polished sample, and X-ray diffraction (XRD) to identify intermetallics in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys.Findings: The results show that the microstructure of cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys in T6 condition consisted a wide range of intermetallic phases. By using various instruments (LM, SEM, XRD) and techniques (imagine, EDS) following intermetallic phases were identified: β-Al5FeSi, α-Al15(FeMn)3Si - in AlSi5Cu1Mg alloy and Al7Cu4Ni, Al12Cu23Ni, Al2CuMg, AlCuFeNi - in AlCu4Ni2Mg2 alloy.Research limitations/implications: In order to complete and confirm obtained results it is recommended to perform further analysis of the investigated aluminium alloys. Therefore it is planned to include in a next studies, microstructure analysis of the alloys by using transmission electron microscopy technique (TEM).Practical implications: Since the morphology, crystallography and chemical composition affect the intermetallic properties, what involves changes of alloy properties, from a practical point of view it is important to understand their formation conditions in order to control final constituents of the alloy microstructure.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phases occurring in the cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys. This study has showed that the chemical phenol extraction method for the cast aluminium alloy is applicable.
Ductile fracture locus of AC4CH-T6 cast aluminium alloy  [PDF]
H. Mae,X. Teng,Y. Bai,T. Wierzbicki
Archives of Computational Materials Science and Surface Engineering , 2009,
Abstract: Purpose: Cast aluminium alloys have found wide application to manufacture lighted-weight components of complex shape in automotive and aerospace industries. To improve the strength and ductility of cast aluminium alloys, it is necessary to study their fracture properties by conducting a series of tests. This study addresses calibration of ductile fracture property of the cast aluminium alloy (AC4CH-T6) made by the gravity die casting with sand mold.Design/methodology/approach: 6 round bar specimens and 6 butterfly specimens are machined from the actual cast component. The tensile tests on the smooth and notched round bar specimens are performed to calibrate the fracture strain in the range of high positive stress triaxialities. The combined loading tests on the butterfly specimens are carried out using a uniquely designed Universal Biaxial Testing Device (UBTD). These tests cover the fracture properties in the rage of low and negative stress triaxialities. Detailed finite element models of all the tests are developed. The fracture locus in the space of the effective plastic strain to fracture and the stress triaxiality are constructed in a wide rage from -1/3 to 1.0.Findings: It is found that material ductility sharply decreases with the stress triaxiality. The material ductility at the negative stress triaxiality is much higher than that in the positive stress triaxiality.Research limitations/implications: Large spread of data is observed for those tests repeated on the same loading configuration, necessitating the statistical analysis of the fracture processes.Practical implications: It is expected that such a fracture criterion would be able to correctly predict the fracture response of actual cast aluminum components under complex loading in the practical applications.Originality/value: The conventional researches focused on the material ductility at the stress triaxiality larger than +1/3. The present study showed the material ductility at the wide range of stress triaxiality from -1/3 to 1.0.
Artificial Neural Networks to Predict of Liquidus Temperature in Hypoeutectic Al-Si Cast Alloys  [PDF]
S. Farahany,M. Erfani,A. Karamoozian,A. Ourdjini
Journal of Applied Sciences , 2010,
Abstract: Determining the liquidus temperature of cast alloys is an important factor in considering the superheating temperature and melt treatment of aluminium-silicon cast alloys. In addition to experimental calculation, the liquidus temperature can also be determined using simulation software for more reliable results. In this study, Artificial Neural Network (ANN) with hyperbolic tangent was selected to predict the liquidus temperature of Al-Si alloys as a function of chemical composition. The neural network was trained with seven input parameters (Si, Fe, Cu, Mn, Mg, Zn and Ti) and one output parameter (liquidus temperature). Training and testing dataset has been chosen from different published works, any casting software and aluminium binary phase diagrams. The accuracy of neural network was verified using values reported in literatures. The result of this investigation has shown that the backpropagation feed forward neural network is accurate enough to predict liquidus temperature.
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