Study of the Microstructure and Crack Evolution Behavior of Al-5Fe-1.5Er Alloy.

Ming Li,Yubao Liu,Huhe Wang,Xiufeng Wu,Zhiming Shi

doi:10.3390/ma12010172

Ming Li, Yubao Liu + Show 3 more

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https://doi.org/10.3390/ma12010172

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Abstract

In this work, the microstructure of Al-5Fe-1.5Er alloy was characterized and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. The effect of microstructure on the behavior of crack initiation and propagation was investigated using in situ tensile testing. The results showed that when 1.5 wt.% Er was added in the Al-5Fe alloy, the microstructure consisted of α-Al matrix, Al3Fe, Al4Er, and Al3Fe + Al4Er eutectic phases. The twin structure of Al3Fe phase was observed, and the twin plane was {001}. Moreover, a continuous concave and convex interface structure of Al4Er was observed. Furthermore, Al3Fe was in the form of a sheet with a clear gap inside. In situ tensile tests of the alloy at room temperature showed that the crack initiation mainly occurred in the Al3Fe phase, and that the crack propagation modes included intergranular and trans-granular expansions. The crack trans-granular expansion was due to the strong binding between Al4Er phases and surrounding organization, whereas the continuous concave and convex interface structure of Al4Er provided a significant meshing effect on the matrix and the eutectic structure.

Highlights

Being among the lightest structural materials, aluminum alloy has the advantages of low density, high specific strength and stiffness, good thermal conductivity and excellent electromagnetic shielding and anti-radiation properties, due to which, it has applications in various fields, including manufacturing, aerospace and electronic communication [1,2,3,4]
Point E represents the Al matrix, whereas the results showed that a small amount of Fe element was dissolved in the matrix
(2) The in situ tensile test at room temperature showed that the cracks were mainly formed inside

Summary

Introduction

Being among the lightest structural materials, aluminum alloy has the advantages of low density, high specific strength and stiffness, good thermal conductivity and excellent electromagnetic shielding and anti-radiation properties, due to which, it has applications in various fields, including manufacturing, aerospace and electronic communication [1,2,3,4]. The alloying effect is one of the most important means to improve the mechanical properties of aluminum alloy. The existing research [5,6,7,8,9,10,11,12,13] has shown that erbium (Er) can improve the mechanical properties of aluminum alloys. Researchers have conducted a lot of experimental work to improve the microstructure and mechanical properties of 8000 series aluminum alloy using Er. Karnesky et al [8,9,10,11,12,13,14] found that the microstructure of 8000 series aluminum alloy was refined due to the addition of Er (0–0.8 wt.%) and formed new granular or needle-like Al4 Er compounds. The study of Che et al [15,16,17,18,19] suggested that, after the addition of Er in the proportion of

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