Akademik Veri Yönetim Sistemi
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, cilt.53, sa.8, ss.2861-2873, 2022 (SCI-Expanded)
The use of secondary aluminum for structural components in the automotive industry is limited by the high Fe contents in recycled alloys which often result in the formation of brittle β-Al5FeSi phase which reduces the ductility of aluminum castings. In this study, a new secondary Al–Si–Mg alloy with high Fe content (about 0.44 wt pct) was developed for die casting applications. Based on thermodynamic modeling, manganese was added to obtain a designed Fe-to-Mn ratio of 2 which successfully suppressed the formation of β-Al5FeSi phase, by forming α-Al15(Fe,Mn)3Si2 phase with rounded or hexagonal morphology. Additionally, a fine needle-like π-Al8FeMg3Si2 phase was also formed within the eutectic regions. The new recycled alloy showed comparable mechanical properties in the as-cast and heat-treated (T5 and T6) conditions to three major primary die cast alloys (≤ 0.2 wt pct Fe) with similar composition. Ductility up to 7.4 pct from tensile elongation was achieved in the as-cast recycled alloy due to the modification and refinement of α-Al15(Fe,Mn)3Si2 by Mn and Sr additions. Tensile elongation was further improved to 9.1 pct after T6 treatment as a result of dissolution of π-Al8FeMg3Si2 phase, defragmentation of α-Al15(Fe,Mn)3Si2, and the spheroidization of Si phase. This new alloy provides a promising path for increasing usage of recycled aluminum with high Fe content in structural die castings for automotive and other applications.