Effect of Nano-Si3N4 Reinforcement on the Microstructure and Mechanical Properties of Laser-Powder-Bed-Fusioned AlSi10Mg Composites

Zhongliang Lu,Fusheng Cao,Yu Han,Kai Miao,Haitian Zhang,Yunpeng Gao,Dichen Li,Xin Deng

doi:10.3390/cryst12030366

Zhongliang Lu, Fusheng Cao + Show 6 more

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https://doi.org/10.3390/cryst12030366

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Abstract

Laser powder bed fusion (LPBF) technology is of great significance to the rapid manufacturing of high-performance metal parts. To improve the mechanical behavior of an LPBFed AlSi10Mg alloy, the influence of nano-Si3N4 reinforcement on densification behavior, microstructure, and tensile property of AlSi10Mg was studied. The experimental results show that 97% relative density of the 3 vol.% nano-Si3N4/AlSi10Mg composite was achieved via optimization of the LPBF process. With the increase in the nano-Si3N4 content, the tensile strength and the yield strength of the composite steadily increase as per the Orowan strengthening mechanism while the elongation decreases. In addition, nano-Si3N4 reinforcement reduces the width of the coarse cell structure region and the thermal influence region of the AlSi10Mg matrix. After annealing, the tensile strength of the nano-Si3N4/AlSi10Mg composite decreases and the elongation increases significantly.

Highlights

Additive manufacturing (AM) technology is revolutionizing the way that traditional products are manufactured, via its unique layer-by-layer superposition fabrication manner based on a 3D model [1] that can help create complex-shaped products with good physical and mechanical properties [2]
For all the nano-Si3N4/AlSi10Mg composites with different nano-Si3N4 contents, laser power, laser scanning speed, as well as hatching space have optimum ranges corresponding to the peak relative density
The energy input during Laser powder bed fusion (LPBF) can be monotonically controlled by laser power, laser scanning speed, hatching space, and layer thickness, the relative density of the nano-Si3N4/AlSi10Mg composites does not increase or decrease with these LPBF parameters

Summary

Introduction

Additive manufacturing (AM) technology is revolutionizing the way that traditional products are manufactured, via its unique layer-by-layer superposition fabrication manner based on a 3D model [1] that can help create complex-shaped products with good physical and mechanical properties [2]. Laser powder bed fusion (LPBF) is one of the advanced AM technologies that provide outstanding advantages in combining shape forming and sintering/melting/casting in a single step. At present, it has wide application prospects in aerospace, biomedicine, automobile engineering, and other fields [3–6]. AlSi10Mg has been proven to be a typical material suitable for LPBF due to its good weldability, admirable hardenability, high thermal conductivity, and favorable corrosion resistance The reasons for these excellent properties are that the near-eutectic composition of Al and Si reduces the solidification range and a small amount of Mg makes AlSi10Mg suitable for heat treatment to harden and strengthen the matrix [10]. Zhou [17] investigated the effects of curvatures on the geometrical performance, defects, microstructure, and mechanical properties of as-built AlSi10Mg parts with curved surfaces

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