Effect of (Pr+Ce) Additions on Microstructure and Mechanical Properties of AlSi5Cu1Mg Alloy

Miao-Miao Fang,Hong Yan,Yong-Hui Sun,Xian-Chen Song

doi:10.3390/app9091856

Abstract

The microstructure and mechanical properties of AlSi5Cu1Mg alloy with (Pr+Ce) addition were investigated by optical microscopy (OM), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The results demonstrated that the rare earth (Pr+Ce) addition refined the grain. The long needle-like eutectic Si phases turned to granual. The secondary dendrite arm spacing (SADS) of the primary α-Al phase with the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached the minimum value, which decreased by 50.2%. The mean length and the aspect ratio of the eutectic Si decreased by 78.8% and 67.4%. The ultimate tensile strength (UTS), the microhardness, and the breaking elongation of the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached a maximum, and increased by 21.5%, 21.7%, and 8.0% compared to the AlSi5Cu1Mg alloy. The fracture examinations manifested in cleaved surfaces and brittle fracture areas, which were seen from the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy. The number of dimples slightly increased.

Highlights

The Al–Si alloy, which accounts for 80% of the aluminum alloy market, has many advantages including excellent castability ratings, high fluidity, and good corrosion resistance, etc
The (Pr+Ce) addition had a refinement effect on the eutectic Si
The morphology of the eutectic Si was modified from an acicular-like shape to a granular shape

Summary

Introduction

The Al–Si alloy, which accounts for 80% of the aluminum alloy market, has many advantages including excellent castability ratings, high fluidity, and good corrosion resistance, etc. The Al–Si alloys were strengthened by the additional metal elements, such as Tungsten [1]. Wu et al [2] considered the effects that Sr additions had on the microstructures and the mechanical properties of Al3Ti/ ADC12. They found that when the Sr content increase to 0.25 wt.%, the coarse dendritic of the primary α-Al phases completely refines, and the acicular or short rod shape of the eutectic silicon changes into a granular shape. The mechanical properties are improved by the addition of Sr, where good UTS and breaking elongation were obtained. Studies [3,4,5,6,7] show that some rare earth (RE) elements play a role in modifying the Al–Si cast aluminum alloys. Song et al [8]

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Results

Conclusion