Microstructure and Tensile Properties of Wire Arc Additive Manufactured 2319 Aluminum Alloy Cross-stringer Structure

Abstract

Wire arc additive manufacturing (WAAM) has the advantages of high material utilization rate, high manufacturing efficiency, and low manufacturing cost. It is suitable for the fabrication of large and complex aviation thin-walled components. There is a lack of systematic investigation on scanning path planning, shape control, microstructure and performance difference of WAAM of cross-stringer structure. A novel layer slicing and path planning method is proposed to solve the problem of insufficient manufacturing accuracy caused by excessive reinforcement in the cross area of stringers. The grain morphology, element distribution, tensile properties, and fracture morphology in different 2319 aluminum alloy WAAMed cross stringer areas are detected and analyzed. The results indicated that the grain morphology and size in different areas of 2319 aluminum alloy WAAMed cross stringer structure are obviously different. The average tensile strength at the top of the WAAM sample is about 20% higher than that at the middle and bottom of it. There are a large number of dimples in the tensile fracture θ (Al2Cu) particle phase. The incoherent precipitation phase increases the lattice distortion energy and enhances the dislocation resistance, which makes the crystal sliding difficult. Therefore, the strength of the material is significantly improved.