Manufacturing Aluminum/Multiwalled Carbon Nanotube Composites via Laser Powder Bed Fusion.

Eo Ryeong Lee,Naoki Takata,Masaki Kato,Se Eun Shin,Makoto Kobashi

doi:10.3390/ma13183927

Abstract

This study provides a novel approach to fabricating Al/C composites using laser powder bed fusion (LPBF) for a wide range of structural applications utilizing Al-matrix composites in additive manufacturing. We investigated the effects of LPBF on the fabrication of aluminum/multiwalled carbon nanotube (Al/MWCNT) composites under 25 different conditions, using varying laser power levels and scan speeds. The microstructures and mechanical properties of the specimens, such as elastic modulus and nanohardness, were analyzed, and trends were identified. We observed favorable sintering behavior under laser conditions with low energy density, which verified the suitability of Al/MWCNT composites for a fabrication process using LPBF. The size and number of pores increased in specimens produced under high energy density conditions, suggesting that they are more influenced by laser power than scan speed. Similarly, the elastic modulus of a specimen was also more affected by laser power than scan speed. In contrast, scan speed had a greater influence on the final nanohardness. Depending on the laser power used, we observed a difference in the crystallographic orientation of the specimens by a laser power during LPBF. When energy density is high, texture development of all samples tended to be more pronounced.

Highlights

Laser powder bed fusion (LPBF) is a promising additive manufacturing technology that enables three-dimensional (3D) shape flexibility in feedstock with various metallic powders at a fast production rate [1]
We found that the highest density of a specimen
Compared to the Al/multiwall carbon nanotubes (MWCNTs) composites fabricated using laser powder bed fusion (LPBF) in previous studies, all specimens produced by this study showed higher nanohardness values and up to 31% higher elastic modulus

Summary

Introduction

Laser powder bed fusion (LPBF) is a promising additive manufacturing technology that enables three-dimensional (3D) shape flexibility in feedstock with various metallic powders at a fast production rate [1]. In the LPBF process, a computer-controlled laser selectively melts the powder bed, which is iterated layer by layer until the final product [3]. Owing to the advantages of LPBF, many studies have tried to analyze and report on commercial alloy powders, such as stainless steels (e.g., AISI316L [4]), titanium (e.g., Ti-6Al-4V [5]), aluminum (e.g., AlSi10Mg [6]), and nickel-based superalloys (e.g., Inconel [7]). Several studies investigated the effect of heat treatment on the mechanical properties with microstructural stability, such as enhanced elongation of selective laser melted AlSi10Mg from 1.4% to 3.9% due to homogeneous microstructure, as reported by Aboulkhair et al [6] or improved strength owing to precipitates in the maraging steels, as described by Jagle et al [7]

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