A hypoeutectic Al-Ni-Mg in situ composite processed by wire-arc additive manufacturing: Phase evolution and mechanical behavior

Beschreibung

The development of novel metallic alloys tailored for additive manufacturing has been in research focus of recent years. While substantial progress has been presented using powder-based processes, relatively little efforts have been made using wire feedstock and most literature in this field is on commercial welding wires. In wire-arc additive manufacturing (WAAM) a metallic wire is fed into an energy source, such as an electric arc, whereby the wire is melted and deposited according to a predefined path. Alloys targeted for additive processing oftentimes exploit the beneficial effects of eutectic reactions. However, no reports have been released so far on eutectic aluminum alloys processed by WAAM other than aluminum-silicon alloys such as aluminum-nickel alloys. The interest in eutectic alloys is based on their advantageous solidification behavior as their rapid solidification reduces their tendencies to form shrinkage cavities and hot cracks. This work deals with the investigation of a novel hypoeutectic Al-Ni-Mg alloy. The eutectic microstructure of Al-Ni alloys consists of a fine-scaled lamellar colony structure. But, as no information on the addition of solid-solution strengtheners such as Mg have been reported so far, this shall be addressed in the present work. We present a comprehensive analysis of the microstructure formation and the resultant mechanical properties of a hypoeutectic Al-Ni-Mg alloy. Microstructure characterization was conducted by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The phase evolution was substantiated by thermodynamic calculations and differential scanning calorimetry (DSC). Corresponding mechanical properties were analyzed using microhardness measurements and tensile testing accompanied by studies of the fracture surfaces. The obtained results are utilized to correlate microstructural features of the hypoeutectic Al-Ni-Mg alloy to the observed mechanical behavior and provide the basis for novel and advanced WAAM-optimized aluminum alloy development.

Zeitraum	27 Sept. 2022 → 29 Sept. 2022
Ereignistitel	MSE 2022
Veranstaltungstyp	Sonstiges
Bekanntheitsgrad	International