Arc (geometry)

Engineering

Fabrication

Metallurgy

Materials science

Elongation

Dendrite (mathematics)

Ultimate tensile strength

Friction stir processing

Ductility (Earth science)

Creep

Porosity

Mechanical engineering

Alternative medicine

Alloy

Mathematics

Microstructure

Eutectic system

Geometry

Composite material

Medicine

Aluminium

Pathology

Journal of Material Science and Technology

To expand the application of wire-arc additive manufacturing (WAAM) in aluminum alloy forming components, it is vitally important to reduce the porosity, refine microstructure, and thereby improve the mechanical properties of the components. In this study, the interlayer friction stir processing (FSP) technique was employed to assist the WAAM of 4043 Al–Si alloy, and the related effects on the microstructure evolutions and mechanical properties of the fabricated builds were systematacially investigated. As compared to the conventional WAAM processing of Al–Si alloy, it was found that the introduction of interlayer FSP can effectively eliminate the pores, and both the α-Al dendrites and Si-rich eutectic network were severely broken up, leading to a remarkable enhancement in ductility and fatigue performance. The average yield strength (YS) and ultimate tensile strength (UTS) of the Al-based components produced by the combination of WAAM and interlayer FSP methods were 88 and 148 MPa, respectively. Meanwhile, the elongation (EL) of 37.5% and 28.8% can be achieved in the horizontal and vertical directions, respectively. Such anisotropy of EL was attributed to the inhomogeneous microstructure in the stir zone (SZ). Notably, the stress concentration can be effectively reduced by the elimination of porosity and Si-rich eutectic network fragmentation by the interlayer FSP, and thus the fatigue behavior was improved with the fatigue strength and elongation increased by ∼28% and ∼108.7%, respectively. It is anticipated that this study will provide a powerful strategy and theoretical guidance for the WAAM fabrication of Al-based alloy components with high ductility and fatigue performance.

Improvement of microstructure and fatigue performance of wire-arc additive manufactured 4043 aluminum alloy assisted by interlayer friction stir processing