Effect of mechanical combined with electromagnetic stirring on the dispersity of carbon fibers in the aluminum matrix

Guanglong Li,Qiwen Zhou,Yingdong Qu,Ruirun Chen,Yaohua Yang,Rongde Li

doi:10.1038/s41598-020-64983-5

Guanglong Li, Qiwen Zhou + Show 4 more

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https://doi.org/10.1038/s41598-020-64983-5

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Abstract

In order to improve the uneven distribution of carbon fibers (CFs) in the matrix by traditional single mechanical stirring, mechanical combined with electromagnetic (M-E) stirring was used to prepare short carbon fibers reinforced aluminum matrix (Csf/Al) composites. The 3-D flow field of aluminum melt under mechanical/M-E stirring were calculated and compared. The calculation results show that the complexity of flow field under M-E stirring could be significantly enhanced relative to a single mechanical stirring, especially there was a strong melt flow near the crucible wall due to the skin effect. It was found that except the inertial force under mechanical stirring and the melt collision with the crucible walls, CFs were also subjected to the electromagnetic force and the oscillating flow between the eddy currents, which would promote the dispersity of the short CFs in the composites. The experimental results are consistent with the calculation results. The experimental results show that the distribution of CFs at each position in the composite samples prepared under M-E stirring was stable. The uniform distribution of CFs in the composites would play an important role in improving the overall performance of the Csf/Al composites.

Highlights

In order to improve the uneven distribution of carbon fibers (CFs) in the matrix by traditional single mechanical stirring, mechanical combined with electromagnetic (M-E) stirring was used to prepare short carbon fibers reinforced aluminum matrix (Csf/Al) composites
It can be known from the previous investigation that even though the Csf/ Al composites can be prepared by mechanical stirring, the local agglomeration of CFs limits the performance of the composites
In order to improve the distribution of CFs in Csf/Al composites by mechanical combined with electromagnetic (M-E) stirring process, it is necessary to have a better understanding of the details of melt flow

Summary

Introduction

In order to improve the uneven distribution of carbon fibers (CFs) in the matrix by traditional single mechanical stirring, mechanical combined with electromagnetic (M-E) stirring was used to prepare short carbon fibers reinforced aluminum matrix (Csf/Al) composites. Singh et al.[11] manufactured the carbon fiber reinforced aluminum matrix composites by a stirring process, but the distribution of fibers was inhomogeneous due to the agglomeration of the CFs. Li et al.[12] used square crucible to prepare Csf/Al composites, which promoted the dispersion of CFs by increasing the turbulence intensity in the melt during the stirring process. When the stirring speed reaches 1000 rpm, the dispersion effect of the short CFs in the matrix can achieve the best, but a small amount of fiber agglomeration still exist in the corners of the matrix It can be known from the previous investigation that even though the Csf/ Al composites can be prepared by mechanical stirring, the local agglomeration of CFs limits the performance of the composites. The dispersion of the short CFs in the matrix and their tensile strength were examined

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