Selective Laser Melting of High Relative Density and High Strength Parts Made of Minor Surface Oxidation Treated Pure Copper Powder

Peng Yang,Xingye Guo,Dingyong He,Zhen Tan,Hanguang Fu,Wei Shao

doi:10.3390/met11121883

Abstract

Pure Copper (Cu) is very difficult to prepare using selective laser melting (SLM) technology. This work successfully prepared the pure Cu with high relative density and high strength by the SLM technology using a surface oxidation treatment. The gas-atomized pure Cu powder was used as the feedstock in this work. Before the SLM process, the pure Cu powder was initially handled using the surface oxidation treatment to coat the powder with an extremely thin layer of Cu2O. The SLMed highly dense specimens contain α-Cu and nano-Cu2O phases. A relationship between the processing parameters (laser power (LP), scanning speed (SS), and hatch space (HS)) and density of Cu alloy in SLM was also investigated. The microstructure of SLMed Cu consists of fine grains with grain sizes ranging from 0.5 to ~30 μm. Tensile testing and detailed microstructural characterization were performed on specimens in the as-SLMed and pure copper state specimens. The mechanical property experiments showed that the specimens prepared by SLM technology containing nano-oxide phases had higher yield strength and tensile strength than that of other SLM-built pure copper. However, the elongation was remarkably decreased compared to other SLM-built pure copper, due to the fine grains and the nano-oxides.

Highlights

Selective laser melting (SLM), as one of the most promising additive manufacturing (AM) technologies based on powder bed fusion technology that produces metallic components with high relative density layer by layer using the laser as the input heat resource, brings tremendous opportunities for fabricating metallic components, especially those with complex structures [1,2,3]
When comparing the surface micro-oxidation of pure copper powder, the best powder formation and the highest density were observed at a temperature of 160 ◦ C and a heating time of 3 min
The melting of copper powder was improved by surface modification and the highly dense SLM-built pure Cu specimens were successfully prepared

Summary

Introduction

Selective laser melting (SLM), as one of the most promising additive manufacturing (AM) technologies based on powder bed fusion technology that produces metallic components with high relative density layer by layer using the laser as the input heat resource, brings tremendous opportunities for fabricating metallic components, especially those with complex structures [1,2,3]. SLM can improve the densification of formed parts by controlling the support size and tilt angle. Studying the effects of support size and tilt angle on the geometric properties of SLMed formed parts can help control the formation properties of the SLMed cellular lattice structure [4,5]. The. SLM technology is widely recognized as a rapid prototyping technique with a delicate microstructure due to the high cooling speed, which might generate a non-equilibrium solidification process. As a result of all the above mechanisms, it gives unique characteristics in the microstructures, phase, chemical composition, and mechanical properties [6,7]

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Results

Conclusion