Abstract
Directed Energy Deposition (DED-Arc), an advanced additive manufacturing process that utilizes an arc heat source, is commonly employed to fabricate large-scale metal
components with complex geometries. The technique involves applying layers of metal, typically in wire or powder form, and melting it using an electric arc. This research investigates the microstructural and mechanical characteristics of DED-Arc, employing GMAW (Gas Metal Arc Welding) of the plate and block components of Aluminum 6061 alloy. Microscopic analyses are performed using Optical Microscopy, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Energy Dispersive X-ray spectroscopy (EDX). Fine-structure analysis revealed that the grain structure consists of distinct interlayer and intralayer regions along the vertical direction of both the plate and block. In contrast, the horizontal direction exhibits a relatively homogeneous microstructure. Additionally, similar inter-layer and intra-layer features are observed along the crosswise dimension in the block. Pores of both macro and micro sizes were detected in the samples of the plate and block. Moreover, the microvoids observed within the block samples were likely caused by inadequate penetration between adjacent layers. Second-phase particles, including α-Al and β-phase Mg₂Si, were found embedded in the matrix and concentrated near the edges. Secondary phase particles were identified both within the matrix and near the boundaries. Microhardness and tensile tests are used to examine the material's mechanical properties. It was observed that the typical value of hardness increases from the lower to the upper area across the plate and block. The 6061 Al alloy plate produced by DED-Arc demonstrates better tensile properties compared to the cast 6061 Al alloy. Due to the presence of significantly larger microvoids and pores in block samples, their tensile properties were considerably reduced. All specimens extracted from the block and thin plate exhibited ductile fractures.

Key words
Aluminum 6061, direct energy deposition, arc energy source, mechanical properties, thin plate, block, microstructure

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