Abstract

The phase transformations in the Al-Ca-Mg-Si system have been studied using thermodynamic calculations and experimental methods. We show that at 10% Magnesium (Mg), depending on the concentrations of calcium (Ca) and silicon (Si), the following phases crystallize first (apart from the aluminum (Al) solid solution): Al4Ca, Mg2Si, and Al2CaSi2. We have found that the major part of the calculated concentration range is covered by the region of the primary crystallization of the Al2CaSi2 phase. Regardless of the Ca and Si content, the solidification of the aluminum-magnesium alloys ends with the following nonvariant eutectic reaction: L → (Al) + Al4Ca + Mg2Si + Al3Mg2. With respect to the temperature and composition of the liquid phase, this reaction is close to the eutectic reaction in the Al-Mg binary system. The addition of Ca and Si to the Al-10% Mg base alloy increases its hardness, reduces its density, and has no negative influence on its corrosion resistance. We have also established that the near-eutectic alloy containing about 3% Ca and 1% Si has the optimum structure.

Highlights

  • Aluminum-magnesium alloys are widely used in various products in the automotive industry, shipbuilding, rocket technology, and other important industries [1,2] due to a successful combination of their properties

  • ), and the points correspond to the invariant correspond to the ternary eutectics (L → (Al) + β11 + β22), and the points correspond to the invariant reactions

  • In alloys with an excess of calcium, the ternary compound disappears as a result of an invariant peritectic reaction, and the solidification proceeds in accordance with the monovariant eutectic reaction L → (Al) + Al4Ca + Mg2Si, following which the alloy becomes three-phase

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Summary

Introduction

Aluminum-magnesium alloys are widely used in various products in the automotive industry, shipbuilding, rocket technology, and other important industries [1,2] due to a successful combination of their properties. We expect that the new alloys will be useful for the production of shaped castings with low density and high corrosion resistance The use of these composite alloys for the production of metallic glass is hardly possible due to the low glass-forming ability [36,37,38] determined by their chemical composition (in particular, a high content of magnesium and the absence of refractory transition metals). As this quaternary system has not yet been studied in detail, the main aims of this study are as follows:. To identify and justify promising compositions for the development of new corrosion-resistant alloys with reduced density

Materials and Methods
Analysis of Al-Ca-Mg-Si Phase Diagram
Si the solid state:
Ca reaction
The calculated
Analysis of the Microstructure and Physical and Mechanical Properties
Primary crystals of Ca-containing in hyper-eutectic quaternary alloys
Mg2 precipitates after and similar treatment
Conclusions
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