2219铝合金电弧增材制造组织及力学性能的非均匀性

Study on the inhomogeneous microstructures and mechanical properties of additively manufactured 2219 aluminum alloy

摘要:

2219铝合金电弧增材制造技术在航天领域具有广泛的应用前景。采用基于CMT工艺的电弧增材制造技术成形了2219铝合金单壁墙试样,并研究了沉积态、固溶态、固溶+时效态的显微组织与力学性能。结果表明显微气孔、θ(Al₂Cu)及富Fe脆性相在层间密集分布形成薄弱带,是导致水平方向和垂直方向力学性能各向异性的原因。垂直方向拉伸时,微裂纹易于在层间形成,塑性较差、抗拉强度较低。为提高WAAM成形的2219铝合金垂直方向力学性能,需尽可能降低丝材中的Fe、Si杂质含量。

Abstract:

Wire and Arc Additive manufacturing (WAAM) of 2219 aluminum alloy parts is a prospective manufacturing technology in the aerospace industry. In this study, the single wall specimens of 2219 aluminum alloy were built by WAAM technology using CMT welding process. The microstructure characteristics in as deposited state, solid solution state and artificial aging state were systematically investigated. It was found that the weakness strip with more micro porosities, θ(Al₂Cu) phases and iron rich phases in the interlayer region resulted in the anisotrpic mechanical properties of the WAAM specimens. When the specimens were tensioned in the vertical direction, cracks formed easily in the interlayer region, and deteriorated the tensile strength and plasticity. In order to increase the mechanical properties of the WAAM 2219 aluminum alloy in the vertical direction, the composition of Fe and Si in the wire should be as low as possible.