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Crystallization Behavior and Properties of Hypereutectic Al-Si Alloys with Different Iron Content

Deev V., Prusov E., Prikhodko O., Ri E., Kutsenko A., Smetanyuk S.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

101--107

EN

Understanding the influence of iron impurity on the formation of the structure and the properties of hypereutectic aluminum-silicon alloys are important for achieving the required quality of castings, especially those obtained from secondary materials. In the present work, the influence of different iron contents (0.3, 1.1, and 2.0 wt.%) on the crystallization process, microstructure and mechanical properties of the Al-15% Si alloy was studied. It is shown that the presence of iron impurity in the Al-15% Si alloy leads to increasing the eutectic crystallization time from 6.2 to 7.6 s at increasing the iron content from 0.3 wt.% to 1.1 wt.%, changing the structure of the alloy eutectic in the solid state. The primary silicon and β-Al5SiFe phase coexist in the structure of the Al-15% Si alloys at a temperature below 575°C in the range of iron concentrations from 0 to 2 wt.% in equilibrium conditions. In the experimental alloys structure, the primary crystals of the β-phase were metallographically detected only in the alloys containing 1.1 and 2 wt.% of iron impurity. Increase of the iron content up to 2 wt.% significantly reduces the mechanical properties of the Al-15% Si alloy due to the formation of large platelet-like inclusions of β-Al5SiFe phase.

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Skurcz liniowy i naprężenia skurczowe w okresie krzepnięcia i stygnięcia stopu AlSi21

Mutwil J.

Archiwum Odlewnictwa

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2006

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R. 6, nr 21/1

93-100

PL

Opisano stanowisko do badania skurczu liniowego i naprężeń skurczowych w odlewie. Przedstawiono badania przebiegu zmian wymiaru liniowego i naprężeń skurczowych w krzepnącym i stygnącym odlewie pręta ze stopu AlSi21. Badania prowadzono w piaskowych i metalowych formach testowych.

EN

An experimental set-up for examination of the progress of linear contraction- and shrinkage stresses in casting has been described. The examinations of linear contraction and shrinkage stresses progress in period of solidification and self-cooling of the rodcasting from hyper-eutectic AlSi21 alloy have been presented. The examinations have been in sand- and metal mould conducted.

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Przyczyny powiększenia twardości siluminu AlSi17 z dodatkami stopowymi po obróbce cieplnej

Piątkowski J., Binczyk F.

Archiwum Nauki o Materiałach

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2002

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T. 23, nr 4

337-349

PL

W pracy przedstawiono wyniki pomiarów twardości HB w stanie po odlaniu oraz po obróbce cieplnej nadeutektycznego siluminu stopowego AlSi17CuNiMg z dodatkami stopowymi Cr, Co, Mo, W i Ti. Silumin modyfikowano fosforem w postaci zaprawy Cu-P. Stwierdzono, że stosowane dodatki pierwiastków wysokotopliwych znacznie podwyższają twardość, co może być korzystne dla elementów silników spalinowych, a zwłaszcza odlewów, tłoków i głowic. Po obróbce cieplnej polegającej na przesycaniu z 470 stopni Celsjusza/4 h/woda i starzeniu w 160 stopniach Celsjusza/6 h/powietrze oraz po wprowadzeniu dodatków stopowych, zwłaszcza Mo i W, uzyskano powiększenie twardości o ponad 30% w stosunku do stopu w stanie po odlaniu. Podwyższenie twardości jest spowodowane rozdrobnieniem i równomiernym rozmieszczeniem kryształów krzemu pierwotnego w objętości odlewu na skutek procesu modyfikacji fosforem, umocnieniem roztworu stałego alfa przez wprowadzenie dodatków stopowych, oraz procesami wydzieleniowymi przebiegającymi podczas obróbki cieplnej. W celu wyjaśnienia przyczyn zwiększenia twardości stopu po obróbce cieplnej przeprowadzono badania składu fazowego. Dyfraktogramy poddano analizie, a w szczególności wartość intensywności i poszerzenia całkowego wysokokątowych linii dyfrakcyjnych dla Al 220, Al 331, Al 222 i Si 331. Zarejestrowane linie dyfrakcyjne dopasowano do teoretycznej funkcji typu Lorentza. Wykazano, że wysokotopliwe dodatki stopowe wpływają na powiększenie iloczynu A x sigma co prowadzi do umocnienia roztworu, a w konsekwencji do zwiększenia twardości siluminów po obróbce cieplnej.

EN

In this work the results of the Brinell hardness BH not modified and after heat treatment of hypereutectic AlSi17CuNiMg alloy with Cr, Co, Mo, W and Ti alloys additions have been shown. It has been found that alloy additions hardness - which may be beneficial for structural components of motorcar significantly increase engine parts particularly for piston cast and cylinder head cast. After heat treatment, which consists of solution 470 degrees centigrade/4 h/water and quench ageing heat treatment 160 degrees centigrade/6 h/air and after loading alloy additions especially Mo and W the increase of hardness about 30% higher than in not modified alloy is obtained. The increase of hardness is caused by size reduction and a uniform distribution of primary silicon crystals in the cast volume and also an effect of modification with phosphorous. The rise of hardness is also the results of consolidation of the solid solution alpha due to the loading alloy additions and emitting processes which take place during the heat treatment. Investigations of X-ray radiography phase analysis have been performed to explain the causes of the increase of the alloy after heat treatment. Intensity values and integral broadening of high-angular diffraction lines for Al 220, 331, 222 and Si 331 have been analysed. Matching the course of the registered diffraction lines to the theoretical Lorentz function has been done. It has been found, that high-melting alloy additions influence the increase of product A x sigma. In consequence we obtain a deformation of the crystal lattice, consolidation of the solution and the increase of hardness of Al alloys after heat treatment.

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Relationship of structure and properties of Al-Si alloys.

Taran Yu.N., Kutsova V.Z., Uzlov K.I.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

588-591

EN

The aim of the present investigation had to be study of combined influence of copper and phosphorous on the structure and properties of hypereutectic Al-Si alloys. In the structure of investigated alloys it could be possible to fix together with aluminium and silicon solid solutions intermetallic phases contained Cu, P, Fe. Alloys modified with phosphorous and copper have average tensile strength higher than syntetic binary ones. At the same time elongation dropping down. In the frame of the present investigation the effect of copper and phosphorous on eutectic and peritectic transformations in Al-Si system has been studied.

5

Phase transitions and structure of hypereutectic Al-Si alloys.

Taran Yu.N., Kutsova V.Z., Uzlov K.I., Evsyukova I.M.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

584-587

EN

Regularities of structural and pase transitions in hypereutectic Al-Si alloys have been studied. Peritectic (740-680 degrees centigrade) and allotropic transformations (680 degrees centigrade) has been found in studied alloys. On the base of experimental data mechanism of peritectic reaction in hypereutectic Al-Si alloys has been proposed.

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Formability modelling of aluminium base PM alloys.

Bagaviev A., Durisin J., Dybiec H., Klein K., Mandziej S., Ziaja G.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1153-1158

EN

The paper presents the results investigations carried out in the frame of the Project CT 96-0750 MicroAlu of Inco-Copernicus program. The investigated materials are PM aluminium alloys with high contents of silicon. The aim of this part is a comprehensive characterisation of microstructure features and specific parameters at the example of an AlSi27Ni6 alloy. The experiments on the plastic and viscoplastic behaviour of this alloy (compressive and tensile tests) at different temperatures and strain rates were done to identify the material properties. The evolution of the microstructure of the tested specimens due to temperature rise and deformation process was investigated with optical and electron microscopy as well as with X-ray analysis technique. The alloy was compacted by a PM extrusion process to a preform and then forged to a final product -connecting rod. From the performed experiments the constitutive parameters were identified and the connecting rod forging process has been simulated by means of a general purpose FEM program.