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1

The Influence of Selected Refining Methods of AlSi7Mg0.3 Silumin on its Quality Index

Czekaj E., Nykiel J., Kwak Z., Garbacz-Klempka A., Nykiel M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

72--78

EN

The publication presents the comparison of selected refining methods (gaseous and/or flux) based on mechanical properties of the obtained secondary silumin EN AC-AlSi7Mg0.3 (in accordance to the European Standard PN-EN 1706:2011). The point of reference was a similar primary alloy produced using pure batch materials. The mechanical properties measured in room temperature were used to calculate the materials quality index. The research showed, that properly carried out refinement process of secondary (recycled) alloys can bring their quality indexes close to those of their primary materials. The goal was to assess the efficiency of selected refining methods when applied to the examined group of casting silumins, by measuring the basic mechanical properties (in room temperature) before and after refining. The practical aspect was to choose an effective (ecologically, technologically and economically) method of refining of secondary EN AC-AlSi7Mg0.3 alloy used to cast car rims for JN METAL company in Ostowiec Świętokrzyski (Poland).

2

The effect of process parameters on residual stress in a friction stir processed cast aluminium alloy AlSi9Mg

Węglowski M. S., Sędek P., Hamilton C.

Engineering Transactions

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2016

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Vol. 64, iss. 3

301--309

EN

The effect of friction stir processing (FSP) on residual stress in a modified cast aluminium alloy AlSi9Mg is presented. The influence of rotational speed and tool type were analysed. The trepanation method was utilized to experimentally measure the residual stress. The results indicate that an increase in rotational speed causes an increase in residual stress. The region around the FSP bead was characterised by tensile residual stress fields which were balanced by compressive stresses in the parent material. A higher residual stress was observed on the advancing side than on the retreating side. Moreover, this asymmetry in residual stress distribution is due to the asymmetry in the volume of material plasticized along the advancing and retreating sides of the stir zone, generating the observed heat distribution. A higher level of residual stress was achieved with the Triflute tool than with a conventional tool.

3

Al-Si and Al-Si-Mg Cast Alloys Shrinkage Porosity Estimation

Samavedam S., Sundarrajan S.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 1

61--68

EN

US A356 and US 413 cast aluminium alloys shrinkage characteristic have been discussed in the present study. Specific volume reduction leads to shrinkage in castings and it can be envisaged as a casting defect. Finite difference based casting process simulation software has been used to study the shrinkage characteristic and it is quantified using mathematical formulae. The three dimensional model of the shrinkage defect has been constructed using CAD application software. Shrinkage characteristic has also been quantified through experimental validation studies and compared well with casting process simulation. Shrinkage characteristic study and control is essential for producing defect free castings. Influence of casting shape on the shrinkage characteristic has been studied in this paper.

4

Artificial neural networks and response surface methodology as a tool for analysis the spindle torque in FSP process

Węglowski M. St.

Computer Methods in Materials Science

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2015

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Vol. 15, No.1

65--70

EN

The article presents the effect of rotational and travelling speeds and down force on the spindle torque acting on the tool in friction stir processing (FSP) process. To find a dependence combining the spindle torque acting on the tool with the rotational speed, travelling speed and the down force, the artificial neural networks (ANN) and response surface methodology (RSM) were applied. Good correlation between experimental set and model was achieved. The best results were gained for the multilayer perceptron type 3-9-1. The results obtained in artificial neural network were compared with those through response surface methodology. Based on achieved results ANN, quadratic and linear models can be recommended to predict the value of spindle torque acting on the tool during FSP process carry out on alloy AlSi9Mg.

PL

W artykule przedstawiono wpływ prędkości obrotowej i przesuwu oraz siły docisku na moment obrotowy działający i narzędzia w trakcie procesu tarciowej modyfikacji warstw wierzchnich FSP. Do wyznaczenia zależności łączącej moment obrotowy działający na narzędzia z prędkością obrotowa prędkością przesuwu i siłą docisku, zastosowano sztuczne sieci: neuronowe (SSN) i metodę powierzchni odpowiedzi (RSM). Osiągnięto zgodność pomiędzy wartościami z badań doświadczalnych i modelami. Najlepsze wyniki uzyskano dla perceptronu wielowarstwowego typ 3-9-1. Uzyskane wyniki dla sztucznej sieci neuronowej porównano z tymi, które uzyskano przy zastosowaniu metody powierzchni odpowiedzi. Na podstawie uzyskanych wyników SSN, modele liniowe i kwadratowe mogą być zalecane do przewidywania wartości momentu obrotowego działającego na narzędzia podczas modyfikacji FSP AISi9Mg.

5

Friction Stir Welding of Elements Made of Cast Aluminium Alloys

Rams B., Pietras A., Mroczka K.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

385--392

EN

The article presents application of FSW method for joining elements made of cast aluminium alloys which are hardly weldable with other known welding techniques. Research’s results of plasticizing process of aluminium and moulding of seam weld during different FSW process’ conditions were also presented. Influence of welding parameters, shape and dimensions of tool on weld structure, welding stability and quality was examined. Application of FSW method was exemplified on welding of hemispheres for valves made of cast aluminium alloy EN AC-43200.

PL

W artykule przedstawiono zastosowanie metody FSW do łączenia elementów z trudno spajanego znanymi technikami spawalniczymi aluminium odlewniczego. Przedstawiono również wyniki badania procesu uplastyczniania aluminium oraz for- mowania się zgrzeiny liniowej w różnych warunkach prowadzenia procesu zgrzewania FSW. Badano wpływ parametrów procesu zgrzewania oraz kształt i wymiary narzędzia na strukturę zgrzein oraz na stabilność i jakość zgrzewania. Zastosowanie metody zgrzewania FSW przedstawiono na przykładnie łączenia czasz kul zaworów wykonanych z odlewniczego stopu aluminium EN AC-43200.

6

Microstructural Characterisation of Friction Stir Processed Cast AlSi9Mg Aluminium Alloy

Węglowski M. S.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 3 spec.

75--78

EN

Aluminium alloy castings become more popular when a refined microstructure and a uniform distribution of Si particles are easily produced. One of the technologies that can fulfil these requirements is Friction Stir Processing (FSP). Therefore, the formation of various microstructural regions during FSP of AlSi9Mg alloy has been studied. It is presented that each of the regions are characterized by unique microstructures. Prior to FSP, the microstructure of a representative as-cast aluminium alloy was composed of Al dendrites and a nonuniform distribution of Si and Fe. FSP microstructurally modified and significantly refined the as-cast material, effectively eliminating the microstructural segregation and porosity of the base material. The characteristic microstructures are reflected in the hardness distribution. The hardness of the modified area was different from the base material.

7

Effect of specific surface fraction of interphase boundaries on mechanical properties of ceramic-metal composites, obtained by pressure infiltration

Chabera P., Boczkowska A., Zych J., Oziębło A., Kurzydłowski K. J.

Kompozyty

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2011

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R. 11, nr 3

202-207

EN

Ceramic-metal composites, obtained via pressure infiltration of porous ceramics Al2O3 by cast aluminium alloy EN AC-AlSi11 (AK11), were studied. As a result, composites of two interpenetrating phases are obtained. They are composed of 30 vol.% of ceramics. The pore sizes of the ceramic preforms varied from 150 to 500 μm. The results of the X-ray tomography proved very good infiltration of the pores by the metal. The residual porosity is approximately 9 vol. %. The obtained microstructure with percolation of the ceramic and metal phases gives the composites good mechanical properties together with the ability to absorb strain energy. Image analysis has been used to evaluate the specific surface fraction of the interphase boundaries (Sv). The presented results of the studies show the effect of the surface fraction of the interphase boundaries of ceramic-metals on the composite compressive strength, hardness and Young's modulus. In addition, the mechanical properties depend on the degree of infiltration. Compression tests for the obtained composites were carried out, and Young's modulus was measured by application of the DIC (Digital Image Correlation) method. Moreover, Brinell hardness tests were performed. The composites microstructure was studied using scanning electron microscopy (SEM). SEM investigations showed that the pores are almost fully filled by the aluminium alloy. The obtained results show that the infiltration method can be used to fabricate composites with percolation of the microstructure. However, the research is at its early stage and will be continued in the sphere of the characteristics of interphase boundaries.

PL

Przedmiotem badań były kompozyty ceramika-metal, otrzymywane w wyniku infiltracji porowatej ceramiki Al2O3 odlewniczym stopem EN AC-AlSi11 (AK11). W wyniku infiltracji ceramicznych kształtek powstają kompozyty o dwóch wzajemnie przenikających się fazach, przy czym udział objętościowy ceramiki stanowi ok. 30% objętości kompozytu. Makrostruktura kompozytu o perkolacji faz ceramiki i metalu nadaje mu zdolność do absorbowania energii. Przeprowadzone badania wykazały wpływ udziału granic międzyfazowych ceramika-metal na właściwości mechaniczne kompozytów. Poprzez zmianę wielkości porów w kształtkach ceramicznych infiltrowanych odlewniczymi stopami aluminium, zachowując przy tym stały udział porowatości otwartej, sterowano względną powierzchnią granic rozdziału ceramika-metal. Na wytrzymałość na ściskanie, twardość i moduł Younga oprócz udziału granic międzyfazowych wpływ ma także stopień przeinfiltrowania ceramiki metalem. Badania te mają charakter wstępny i będą kontynuowane w zakresie charakteryzacji granic rozdziału. Uzyskane wyniki dają możliwość uzyskania tą drogą nowych materiałów o właściwościach łączących pozytywne cechy składników kompozytu, w którym osnową jest tworzywo ceramiczne, a fazą wypełniającą pory metal

8

Ductile fracture locus of AC4CH-T6 cast aluminium alloy

Mae H., Teng X., Bai Y., Wierzbicki T.

Archives of Computational Materials Science and Surface Engineering

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2009

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Vol. 1, nr 2

100-105

EN

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.

9

Effect of selected microadditives on the mechanical properties of aluminium alloys

Rzadkosz S., Staszczak L.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 1

85-88

EN

iron in the process of solutioning and ageing of these alloys was described. Basing on the results of investigations, a comparative analysis was made to disclose the effect of low content (microadditives) of the elements, like Mn, Ti, Zr, B, Cr, Ni, Zn, Sn, Cd, In, Mg, Sb, and Ag on the primary structure of castings, mainly on the morphology of iron-bonding intermetallic phases. The studies also allowed for an effect of these elements on dispersion hardening of the examined alloys, reflected in an improvement of the principal mechanical properties (Rm, A5, HV), and on the kinetics of ageing. Tin, cadmium and indium, added in an amount of 0,1 – 0,15 %, were reported to have the strong-est effect on the process of dispersion hardening. Beneficial effect on the morphology of iron phases have manganese, chromium and nickel.

10

Corrosion characteristics of laser surface remelted Al-Si alloy.

Serbiński W., Olive J.M., Frayret J.P.

Inżynieria Materiałowa

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2001

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R. XXII, nr 5

812-815

EN

The effects of laser surface remelting at cryogenic conditions on the local chemical compositions, microstructure and corrosion characteristics of AlSi13Mg1CuNi alloy have been presented. The beneficial effect of laser treatment on the corrosion behaviour of the cast aluminium alloy in 0.01 M H2SO4 solution was observed.

PL

Przedstawiono wpływ laserowego przetapiania w warunkach kriogenicznych na lokalny skład chemiczny, mikrostrukturę i charakterystyki korozyjne stopu AlSi13Mg1CuNi. Uzyskano pozytywny wpływ obróbki laserowej na zachowanie korozyjne odlewniczego stopu aluminium w roztworze 0.01 M H2SO4.