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P.J. Morais, B Gomes, P. Santos, M. Gomes, R. Gradinger, M. Schnall, S. Bozorgi, T. Klein, D. Fleischhacker, P. Warczok, A. Falahati:
"Characterisation of a High-Performance Al-Zn-Mg-Cu Alloy Designed for Wire Arc Additive Manufacturing";
Materials, 13 (2020), 7, 1610.

Ever-increasing demands of industrial manufacturing regarding mechanical properties
require the development of novel alloys designed towards the respective manufacturing process.
Here, we consider wire arc additive manufacturing. To this end, Al alloys with additions of Zn,
Mg and Cu have been designed considering the requirements of good mechanical properties and
limited hot cracking susceptibility. The samples were produced using the cold metal transfer pulse
advanced (CMT-PADV) technique, known for its ability to produce lower porosity parts with smaller
grain size. After material simulations to determine the optimal heat treatment, the samples were
solution heat treated, quenched and aged to enhance their mechanical performance. Chemical
analysis, mechanical properties and microstructure evolution were evaluated using optical light
microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence
analysis and X-ray radiography, as well as tensile, fatigue and hardness tests. The objective of this
research was to evaluate in detail the mechanical properties and microstructure of the newly designed
high-performance Al-Zn-based alloy before and after ageing heat treatment. The only defects found
in the parts built under optimised conditions were small dispersed porosities, without any visible
cracks or lack of fusion. Furthermore, the mechanical properties are superior to those of commercial
7xxx alloys and remarkably independent of the testing direction (parallel or perpendicular to the
deposit beads). The presented analyses are very promising regarding additive manufacturing of
high-strength aluminium alloys.

wire arc additive manufacturing; precipitation hardening; Al-Zn-Mg-Cu alloys; microstructure characterisation; mechanical properties

http://dx.doi.org/10.3390/ma13071610