Effect of electron beam energy densities on the surface morphology and tensile property of additively manufactured Al-Mg alloy

• As the increase of electron beam energy density, the width and depth of intergranular cracks are increased. • The preferred microstructure morphology and grain growth orientation are achieved at the condition of EBED = 10 J/cm 2 . • When the EBED is 10 J/cm 2 , the tensile property of additively manufactured Al-Mg sample get a significant improvement. Al-Mg alloys samples, after wire arc additive manufacturing based on cold metal transfer, have uneven microstructure, heterogeneous distribution of precipitate and elements, and even nonuniformity mechanical properties. Electron beam surface treatment (EBST) can effectively improve this phenomenon to some degree. In this study, the equipment of SOLO automatic with the electron beam is firstly adopted to develop surface treatment on wire-arc-additive- manufacturing Al-Mg specimens. Three electron beam energy densities (5, 10, 15 J/cm 2 ) were set to investigate the effect of electron beam densities on surface microstructure, phase composition, elements distribution and tensile property of Al-Mg samples. As the irritation energy density increasing, the clarity of grain boundaries was heightened, the element Mg was evaporated furtherly and the thickness of the modification layer increased. Whereas, the surface microstructure morphology is relatively even and extending in the depth of intergranular cracks was prevented when the EBED is 10 J/cm 2 . Different EBST processes did not affect the phase composition of WAAM-CMT fabricated Al-Mg samples. However, the crystallization and tensile strength of Al-Mg alloy are optimum at the condition EBED = 10 J/cm 2 .