New Strategy to Improve the Mechanical Properties in Cast Al–Mg–Fe Alloys by the Formation of Al–AlFe Eutectic

Abstract

Fe‐containing intermetallics are often detrimental to the mechanical properties in aluminum alloy. However, an Al–Fe alloy system can form an Al + AlFe eutectic structure in a narrow freezing range, providing the fine Al13Fe4 or Al6Fe intermetallics. Herein, the ternary Al–Mg–Fe alloy is selected to achieve the Al + AlFe eutectic structure composition and form fine AlFe intermetallics for improving the strength and ductility of Al–Mg cast alloy. The results show that as the composition of Al–Mg–Fe alloy is closer to the Al + AlFe eutectic composition, the amount of coarse Al13Fe4 intermetallics decreases, whereas the amount of fine Al + Al13Fe4 eutectic increases. The microstructural evolution results in the improvement of yield strength (72.8–92.4 MPa), tensile strength (126.1–213.7 MPa), and the elongation (2.5–6.2%). This work provides a new strategy to improve the mechanical properties in Al–Mg cast alloy.