Wire Oscillating Laser Additive Manufacturing of 2319 Aluminum Alloy: Optimization of Process Parameters, Microstructure, and Mechanical Properties

Abstract

In this study, a wire oscillating laser additive manufacturing (O-WLAM) process was used to deposit 2319 aluminum alloy samples. The optimization of the deposition process parameters made it possible to obtain samples with smooth surfaces and extremely low porosities. The effects of the deposition parameters on the formability and evolution of the microstructure and mechanical properties before and after heat treatment were studied. The oscillating laser deposition of 2319 aluminum alloy, especially the circular oscillation mode, significantly reduced the porosity and improved the process stability and formability compared with non-oscillating laser deposition. There were clear boundaries between the deposition units in the deposition state, the interior of which was dominated by columnar crystals with many rod- and point-shaped precipitates. After the heat treatment, the θ phase was significantly dissolved. The residual dot- and rod-shaped θ ' phases were dispersedly distributed, exhibiting an obvious precipitation-hardening effect. The samples in the as-deposited state had a tensile strength of 245–265 MPa, an elongation of approximately 12.6%, and an 87 HV microhardness. After heat treatment at 530°C for 20 h and aging at 175°C for 18 h, the tensile strength, elongation, and microhardness reached 425–440 MPa, approximately 10%, and 153 HV, respectively. The performance improved significantly without significant anisotropy. Compared with the samples produced by wire arc additive manufacturing (WAAM), the tensile strength increased by approximately 10%, and the strength and microhardness were significantly improved.