The hot deformation behaviour of laser powder bed fusion deposited Al–Si–Cu alloy processed by high-pressure torsion

Abstract

The tensile properties of an ultrafine-grained Al–9%Si–3%Cu alloy deposited by the laser powder bed fusion process have been investigated in this work. The additively manufactured (AM) alloy was subjected to high-pressure torsion processing at room temperature successfully at different number of turns in HPT and then inspected through hot tensile testing at 298 and 573 K using strain rates ranging from 10–1 to 10–4 s−1. The processed alloy showed extensive refinement and high dislocation density that was associated with considerable strength at ambient temperature. The as-deposited and processed samples of the alloy exhibited significantly higher tensile strength and elongation under hot deformation conditions compared with their cast counterpart alloys. The room temperature-HPT processing presented ultrafine α-Al and well-distributed nanosized eutectic Si particles which significantly improved the tensile behaviour and thermal stability of the processed microstructures. The formation of fibrous structures has enhanced the flow behaviour and cavitation resistance at the elevated testing temperature. The current work indicates the impact of room temperature-HPT processing on the mechanical performance of the controllable AM-deposited alloy to meet industrial needs without further heat treatments or alloying additions.