Synchronous-hammer-forging-assisted wire arc additive manufacturing Al-Mg alloy

The plastic deformation-assisted wire arc additive manufacturing (WAAM) technology based on the hammerforging method has essential application prospects in preparing high-dense fine-grain aluminum alloy components. However, the existing interlayer hammer-forging method has limitations, such as insufficient hammering force and high demand for hammering times when obtaining large plastic deformation. To effectively solve these problems, this paper proposed synchronous-hammer-forging-assisted WAAM technology and systematically studied its effects on the macroscopic morphology, microstructure, pores evolution, and mechanical properties of WAAM Al-Mg alloy specimens. The results show that under the synchronous hammer-forging (SHF) condition, a large plastic deformation of 33.97% can be achieved by the 80 N hammer forging force, and the surface flatness of the specimen was significantly improved. The grain size of the specimen was reduced from 105.92 & mu;m in the deposited state to 37.15 & mu;m in the hammered specimen by 64.93% with a significant equiaxed effect. Simultaneously, with the application of SHF technology and the increasing hammer-forging force, the precipitated phase dominated by Al3Mg2 was broken. The pores in the specimen changed from round to narrow and elongated shape with only 0.0065% porosity. The number of pores, equivalent diameter, and surface area were reduced by 68.33%, 13.75%, and 67.24%, respectively. The yield strength and ultimate tensile strength of the hammerforged specimens reached 250.37 MPa and 315.03 MPa, respectively, which were 36.28% and 8.95% higher than those of the deposited specimens, and still maintained a high elongation rate of 36.11%.

Automated summary

This paper proposes a synchronous-hammer-forging-assisted WAAM technology and systematically studies its effects on the macroscopic morphology, microstructure, pores evolution, and mechanical properties of WAAM Al-Mg alloy specimens. The results show that under the synchronous hammer-forging condition, a large plastic deformation of 33.97% can be achieved, and the surface flatness of the specimen is significantly improved. Furthermore, the use of synchronous hammer-forging technology and increased hammer-forging force breaks the precipitated phase dominated by Al3Mg2 and reduces the number and size of pores, resulting in higher yield and tensile strength.