Effect of Cooling Rate on the Microstructure Evolution and Mechanical Properties of Iron-Rich Al-Si Alloy.

Xiao Shen,Xin Wang,Lichen Zhao,Chunxiang Cui,Shuiqing Liu,Zirui Li,Pan Gong,Xu Han

doi:10.3390/ma15020411

Xiao Shen, Xin Wang + Show 6 more

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https://doi.org/10.3390/ma15020411

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Abstract

The mechanical properties of iron-rich Al–Si alloy is limited by the existence of plenty of the iron-rich phase (β-Al5FeSi), whose unfavorable morphology not only splits the matrix but also causes both stress concentration and interface mismatch with the Al matrix. The effect of the cooling rate on the tensile properties of Fe-rich Al–Si alloy was studied by the melt spinning method at different rotating speeds. At the traditional casting cooling rate of ~10 K/s, the size of the needle-like β-Al5FeSi phase is about 80 μm. In contrast, the size of the β-Al5FeSi phase is reduced to 500 nm and the morphology changes to a granular morphology with the high cooling rate of ~104 K/s. With the increase of the cooling rate, the morphology of the β-Al5FeSi phase is optimized, meanwhile the tensile properties of Fe-rich Al–Si alloy are greatly improved. The improved tensile properties of the Fe-rich Al-Si alloy is attributed to the combination of Fe-rich reinforced particles and the granular silicon phase provided by the high cooling rate of the melt spinning method.

Highlights

Accepted: 4 January 2022Recycled aluminum is obtained through the recycling of waste aluminum products.The production energy consumption is only 3% to 5% of the energy consumption of primary aluminum [1]
For a low cooling rate sample, the ingots were remelted by the induction smelting method, during which it was poured into the preheated 200 ◦ C steel mold with a cavity diameter of 20 mm and a height of 120 mm, which was denoted as the C1 alloy
It is noteworthy that the iron-rich phase disappeared in the matrix as the cooling rate continued to increase to 2.4 × 104 K/s

Summary

Introduction

Recycled aluminum is obtained through the recycling of waste aluminum products. The production energy consumption is only 3% to 5% of the energy consumption of primary aluminum [1]. Many researchers are working to modify the morphology of β-Al5 FeSi phases, such as by adding the alloying elements Mn, Nb, Co, Sc, Er, etc. Increasing the melt superheat and heat treatment are effective ways to improve the morphology of the iron-rich phase. The addition of the above elements only changes the morphology of the iron-rich phase, brings some technical problems, and further increases the difficulty of the secondary resource recovery of Al–Si alloys. Increasing the cooling rate is an effective way to change the morphology of an intermetallic. The microstructure evolution has been reported to be dependent on the cooling rate and Fe content in the Al–Si alloy [17,18]. Through in-depth analysis of the phase microstructure morphology of β-Al5 FeSi under different cooling rates, the solidification path and formation conditions are discussed. The effect of the cooling rates on the microstructure and tensile properties using the rapid solidification technology is further investigated

Materials and Methods

Results and Discussion

Conclusions