Effect of Deposition Strategies on the Microstructure and Tensile Properties of Wire Arc Additive Manufactured Al-5Si Alloys

Abstract

4043 Al-5Si alloy components were fabricated by wire and arc additive manufacturing based on cold metal transfer (WAAM-CMT). Three deposition strategies, i.e. the method of building the layers and tracks (Line 90°, Cycle line 90°, and Line 45°), were employed during the process, and their impact on the microstructure and tensile properties of the deposited Al-5Si alloy was evaluated. Results showed that the samples with different deposition strategies exhibited similar phase composition (α-Al, Si phase, and Al9Si phase), but various deposited layer size, grain size, and Si morphology owing to different deposition strategies. Recrystallization was observed in all deposition processes. The average micro-hardness was ~ 52.3 Hv, yield strength (YS) varied between 130 and 150 MPa, ultimate tensile strength (UTS) changed between 200 and 230 MPa and elongation (EL) ranged between 10 and 12%. Based on the fractographic analysis, the fracture mechanism was identified to be due to the presence of numbers of sharp-angled defects like cracks and chain-like micro-pores.