Fractal Dimension Characterization of Joint Surface Morphology on Dissimilar Friction Stir Lap Welding of Al/Mg.

Yadong Zhao,Zhipeng Zhang,Haixiao Zhang,Shuguang Wang,Hongbao Cui,Xuefeng Guo,Yalong Luo,Yangming Zhang

doi:10.3390/ma12233941

Yadong Zhao, Zhipeng Zhang + Show 6 more

Open Access

https://doi.org/10.3390/ma12233941

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Abstract

The joint surface of the 1060 aluminum and AZ31 magnesium alloy was prepared through friction stir lap welding (FSLW) under different welding process parameters. The joint surface was characterized three-dimensionally using a three-dimensional (3D) optical profiler, and the coordinate data were obtained. The fractal dimension of the joint surface was calculated by the box-width transformation method using a MATLAB program. Furthermore, the influence of the welding process parameters on the fractal dimension of the joint surface was studied. The response surface model was established based on the principle of central composite design (CCD), and analysis of variance (ANOVA) was carried out to test the accuracy of the response surface. The results showed that the joint surface morphology had fractal characteristics, and the fractal dimension could be used as an index to characterize the quality of the joint surface. The change of the welding process parameters had a great impact on the fractal dimension of the joint surface, the interaction between the parameters was small, and the fitting accuracy of the response surface model was high. The fractal dimension of the joint surface decreased with the increase in the welding and rotational speeds and the effect of the rotational speed was more significant.

Highlights

Aluminum alloys have good plasticity and high corrosion resistance
Friction stir welding (FSW) is a new type of solid-phase connection technology, which is mainly realized by the plastic flow of high-temperature metals
The joint surface was scanned by a 3D non-contact optical profiler, and the 3D surface morphology data

Summary

Introduction

Aluminum alloys have good plasticity and high corrosion resistance. Magnesium alloys have low densities and high specific strengths and heat transfer capacities. Friction stir welding (FSW) is a new type of solid-phase connection technology, which is mainly realized by the plastic flow of high-temperature metals. It has become an ideal connection technology for these two lightweight alloy materials because it produces no smoke or arc light, involves a simple pre-welding treatment, and produces small welding deformation during the welding process. It prevents defects such as cracks, porosity, and inclusions caused by fusion welding [4]

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