Microstructure evolution and mechanical properties of laser additive manufacturing of high strength Al-Cu-Mg alloy

摘要

Aluminum alloys have been extensively researched because of its higher strength to weight ratio than conventional steel. Laser based direct energy deposition process has been applied to manufacture solid thin wall samples using commercial gas atomized Al 2024 powder. The effects of unidirectional laser scanning deposition and bidirectional scanning deposition on the forming properties were compared. The evolution of macro-and microstructures of laser deposited Al 2024 samples was investigated using X-ray diffraction, optical microscopy, scanning electron microscopy and electron backscatter diffraction. It was shown that the deposition pattern played a significant role in the evolution of microstructural and grains orientation. The effects of temperature gradients and the shape of the molten pool on the morphology and orientation of the microstructure were discussed under two different deposition patterns. Ultimate tensile strength of 276 MPa and yield strength of 175 MPa was achieved for the DEDed Al 2024 parts.