Abstract

The paper presents the results of microstructure tests of EN AC-46000 hypoeutectic Al–Si alloy with and without high-melting-point elements: chromium, molybdenum, vanadium, and tungsten. The above-mentioned elements were used individually or simultaneously in various combinations. The tested castings were made using two technologies: shell molding and high pressure die casting (HPDC). Using X-ray diffraction and microanalysis of the chemical composition an attempt to determine the phase structure of the tested alloy was made. It has been shown that the microstructure of the base alloy consists of dendrites of α(Al) solid solution and complex eutectic mixtures: ternary α(Al) + Al15(Fe,Mn)3Si2 + β(Si) and quaternary α(Al) + Al2Cu + AlSiCuFeMgMnNi + β(Si). High-melting point elements, regardless of the combination used, attach mainly to intermetallic phases rich in Fe and form the Al15(Fe,Mn,M)3Si2 phase, where M is any high melting point element or a combination of such elements. It has been shown that the area fraction of the above-mentioned phase increases with increasing content of high melting point elements. A greater area fraction of the Al15(Fe,Mn,M)3Si2 phase in the casting from the shell mold in relation to the high pressure die casting has been also found.

Highlights

  • Among the many aluminum alloys AlSi9Cu3(Fe) (EN AC-46000) is a typical high pressure die casting alloy

  • The data presented therein shows the presence of α(Al) solid solution dendrites, α(Al) + β(Si) eutectic mixture, Al2 Cu and iron-rich intermetallic phases in the microstructure

  • This paper presents the changes in the microstructure of multi-component Al-Si alloy on the example of EN AC-46000 alloy occurring as a result of Cr, Mo, V, and W additions in various amounts and combinations

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Summary

Introduction

Among the many aluminum alloys AlSi9Cu3(Fe) (EN AC-46000) is a typical high pressure die casting alloy. The data presented therein shows the presence of α(Al) solid solution dendrites, α(Al) + β(Si) eutectic mixture, Al2 Cu and iron-rich intermetallic phases in the microstructure These phases, depending on the concentration of Fe, Mn, and Cr, can be characterized by a different phase structure and morphology. The papers [28,29,30] present the results of a statistical analysis of the effect of Cr, Mo, V, and W in the HPDC aluminum alloy on its mechanical properties (tensile strength, yield point, elongation, and hardness). They show the possibility of increasing the above mentioned properties by the high melting point elements. This paper presents the changes in the microstructure of multi-component Al-Si alloy on the example of EN AC-46000 alloy occurring as a result of Cr, Mo, V, and W additions in various amounts and combinations

Materials and Methods
Results
Microstructure of the base
Cu indicate that may bephase
10. Microstructure
Si2 phase
13. Microstructure addition of of
16. Changes
Discussion
Conclusions
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