Research On Microstructure And Property Of 2319 Aluminum Alloy By Wire Arc Additive Manufacturing

In order to improve the precision and property of aluminum alloy components using wire arc additive manufacturing,ER2319 aluminum alloy wire were welded with CMT model.Some additive manufacturing sample were heated treatment or made under longitudinal magnetic field then the properties and microstructure of the samples were studied.The surface precision of 2319 aluminum alloy components were not satisfying for user and need to be improved.The microstructure was composed of dendrites,equiaxed grains and columnar crystal,which was layered.Theα-Al andθ（Al₂Cu）phases were found.The mechanical properties with X,Y and Z direction of the sample were studied.It was found that the sample properties were obvious anisotropic.The Y directional mechanical properties were the best,the tensile strength was 249 MPa,the yield strength was 175 MPa,and the elongation was 20.52%.In order to improve the mechanical properties of as-deposited sample,different heat treatment process was executed.The optimized heat treatment process was selected,which was T6（540℃/5 h+175℃/6 h）process.After solution treatment,supersaturation solid solution was formed in Al matrix,and fine dispersion phase precipitated after aging treatment.The phase compositions wereα-Al andθ（Al₂Cu）.The mechanical properties of the three directions of X,Y and Z were greatly improved after T6 treatment.The tensile strength of Y direction was 499MPa,the yield strength was 385 MPa,and the elongation was 19.58%.The main strengthening mechanism was dispersion strengthening.The surface of the sample was smooth and clean,the weld bead was uniform and straight under longitudinal magnetic field additive manufacturing technologies.The longitudinal magnetic field contribute to promote the formation of equiaxed grains,and reduce the grains size.The distribution of pores changed from concentrated distribution between layers to scattered distribution in the whole sample.The mechanical properties were greatly improved after the longitudinal magnetic field was applied,especially in the C+P+A welding mode.The tensile strength of Y direction was 350 MPa,the yield strength was 231 MPa,and the elongation was 18.93%.Through observed the 2319 aluminum alloy component,it showed that the forming condition of“cross-weld”joint was the best when the longitudinal magnetic field was applied.