Fabrication of bulk Al-Co-Cr-Fe-Ni high-entropy alloy using combined cable wire arc additive manufacturing (CCW-AAM): Microstructure and mechanical properties

Abstract

Additive manufacturing is a very promising manufacturing method widely used in various industries. In this study, for the first time, a new type of combined cable wire (CCW) with multi-element composition has been designed and developed for arc additive manufacturing (AAM) of non-equiatomic Al-Co-Cr-Fe-Ni high-entropy alloy. CCW composed of 7 filaments and 5 elements has the advantages of high deposition efficiency, self-rotation of welding arc and energy saving capability. Thin HEA walls were fabricated under pure argon gas using cold metal transfer technology. Microstructural observations of the developed HEA reveal (i) BCC and FCC phases, (ii) Good bonding between layers and (iii) defect-free microstructure. The developed alloy exhibits high compression strength (∼2.9 GPa) coupled with high elongation (∼42 %) values (possess both strength and ductility). It has been identified that by varying the heat input via torch travel speed, the microstructure and mechanical properties of the HEA can be controlled. From this feasibility study, it has been proved that the innovative CCW method can be used to manufacture HEAs with CCW-AAM. Further, the study highlights the advantage of the rapid cooling involved in the CCW-AAM process which gives rise to superior mechanical properties.