Arc welding of dissimilar aluminum alloys is in high demand in industry but often challenging in practice. Dissonant material properties between the base metals often lead to solidification cracking in the weld metal upon cooling. Here, we report a nano-treatment approach that infuses TiC nanoparticles into filler material mimicking commercial ER5183 to successfully join dissimilar systems of AA2024 + AA5083 and AA2024 + AA7075 with the gas-tungsten arc welding process. Welded specimens were free of hot cracking, and microstructural studies revealed globular, refined grains smaller than 20 µm in the weld metals of both systems. Mechanical properties of both systems were examined with microhardness and tensile testing, and they showed sound behavior in their as-welded conditions. Nano-treatment therefore presents a new way to reliably weld dissimilar systems that are traditionally considered unweldable
Purpose
Additive manufacturing (AM) can achieve significant weight savings with only minor compromises in strength if high-performance wrought aluminum alloys are used as feedstock. Despite the advantages in strength that aluminum alloys (AA) 6061 offer, they cannot be manufactured via printing because of hot cracking and other solidification problems. The purpose of this study is to achieve high-quality printing of AA6061 with nanotreated wires.
Design/methodology/approach
Nanotreating was used to modify the AA6061 alloy composition by adding a small fraction of nanoparticles to enhance the alloy’s manufacturability and resultant properties. Wire arc additive manufacturing (WAAM) was used to print the nanotreated AA6061 wire feedstock. The microstructure of the printed AA6061 was characterized by X-ray crystallography, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy mapping. The microhardness profile, tensile behavior and fracture surface were analyzed.
Findings
This work successfully used WAAM to print nanotreated AA 6061 components. The resulting AA6061 parts were crack-free, with exceptional grain morphology and superior mechanical properties. Owing to the excellent size control capabilities of nanoparticles, a homogeneous distribution of small grains was maintained in all deposited layers, even during repeated thermal cycles.
Originality/value
Previous studies have not successfully printed AA6061 using WAAM. Conventional WAAM products exhibit anisotropic mechanical properties. The nanotreated AA6061 was successfully printed to achieve homogeneous microhardness and isotropic tensile properties. The promising results of this study reflect the great potential of nanotech metallurgy as applied to the WAAM process.
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