Study of Refinement and Morphology Change of AlFeSi Phase in A380 Alloy due to Addition of Ca, Sr/ Ca, Mn and Mn, Sr

Abstract

While aluminum-silicon (Al-Si) alloys are one of the most versatile aluminum alloys, iron is considered one of the most harmful elements in Al-Si diecasting application. Its presence leads to the precipitation of many AlFeSi intermetallic phases and unacceptable mechanical properties, such as reduction in ductility. Thus controlling the fraction and morphology of the AlFeSi phase, especially the β-AlFeSi phase is an important way to improve the ductility of Al-Si die casting alloys. In this article, Ca/Mn, Ca/Sr and Sr/Mn elements were added into A380 alloys to study the effect of combined element addition on the morphology change of the AlFeSi phase. Sr and Ca addition can impair the modication effect and introduce sludge. Mn and Ca, Mn and Sr can result in a microstructure consisting of fcc α-Al, modi ed eutectic Si, α-AlFeSi Chinese script phases and a re ned platelet β-phase. However, use of high cooling rates can better re ne the morphology of the AlFeSi phase and lead to a better alloy product.

Effect of La Addition on Solidification Behavior and Phase Composition of Cast Al-Mg-Si Alloy

“…For an explanation of intermetallic formation, we discovered very extensive recent efforts on Si-alternative eutectic-forming elements (Ce, Ni, Ca, La, etc.). Meanwhile, there are similar compounds, Al 2 CeSi 2 [1][2][3] and Al 2 CaSi 2 [34], observed in Al-Si alloys that show a needle-like shape similar to the AlLaSi phase in the present work. Based on this, it is most likely that the composition of the observed AlLaSi phase is the same as of Al 2 LaSi 2, corresponding to the same space group P3m1 as the ternary Al 2 CeSi 2 and Al 2 CaSi 2 [26].…”

Growth dynamics of faceted Al13Fe4 intermetallic revealed by high-speed synchrotron X-ray quantification

“…Much research focused on the β-Al5FeSi phase [19,33,36], as it plays an important role in the mechanical performance of Al-Si based Al alloys. However, the plate-shaped β intermetallics are very thin [37] and as a result of its 3D morphology has not been resolved clearly by high-speed synchrotron X-ray tomography which usually has relatively low spatial resolutions (a few μm [38,39]). Al13Fe4 intermetallic in Al-Fe alloys, on the other hand, could grow into large faceted morphology [40], potentially resolvable by high-speed synchrotron tomography.…”

Effect of Heat Treatment Process and Optimization of Its Parameters on Mechanical Properties and Microstructure of the AlSi11(Fe) Alloy

“…Isolated Fe-rich intermetallic phase precipitations are visible against the α(Al) phase background. Thin and acicular precipitations are the β(AlFeSi) phase [ 78 , 79 , 83 , 85 ], and the Chinese script precipitations are the α(AlFeSi) phase [ 9 , 86 , 87 ]. The minor solubility of iron in α(Al) and acicular morphology of the β(AlFeSi) phase cause that, as a rule, they retain their morphology even after long-lasting heating at temperatures close to the solidus equilibrium, causing the deterioration of the strength and plasticity of Al-Si alloy [ 88 , 89 ] castings and initiation of cracks under load [ 83 ].…”