丝材3D打印2024/7055铝合金梯度结构组织与性能分析

大型高强度轻质铝合金整体结构件在航空航天装备结构中应用广泛。为充分发挥不同材料的性能优势,可将两种以上的铝合金材料通过增材制造技术整体成型,从而制造出兼顾功能与减重要求的整体梯度结构件。为此,提出了一种多丝材电弧增材制造铝合金梯度结构件的制备方法,实现了航空结构常用的2024/7055铝合金梯度结构的3D打印,并对梯度结构进行了宏/微观组织、气孔缺陷、过渡区元素含量以及力学性能等进行了全面的分析。研究结果表明：通过多丝材增材制造打印的2024/7055铝合金梯度结构连接良好、过渡区域连续；梯度区域两种材料的晶粒组成不同,2024铝合金由等轴晶粒组成,而7055由短柱状晶粒组成；气孔在空间分布中呈条状分布,并且两种合金Zn元素含量不同,导致力学性能差异较大；当材料组分占比为2024(25%)/7055(75%)时,力学性能最好,材料折损率最低。

Microstructure and Properties Analysis of 2024 / 7055 Aluminum Alloy Gradient Structure using 3D Printing of Filament

Large-scale high-strength lightweight aluminum alloy monolithic components are widely used in the structure of aerospace equipment. In order to give full play to the performance advantages of different materials, two or more aluminum alloy materials can be integrally formed by additive manufacturing technique, thereby manufacturing an overall gradient structural part that takes into account the requirements of function and weight reduction. For this reason, a preparation method of multi-wire arc additive manufacturing aluminum alloy gradient structure was proposed, which realized the 3D printing of 2024/7055 aluminum alloy gradient structure commonly used in aviation structure, and the macro/microstructure, stomatal defects, elements content in the transition zone and mechanical properties had been comprehensively analyzed. The research results show that the 2024/7055 aluminum alloy gradient structure printed by multi-wire additive manufacturing is well connected and the transition area is continuous; the crystal grain composition of the two materials in the gradient area is different: the 2024 aluminum alloy is composed of equiaxed grains, while the 7055 aluminum alloy is composed of short prismatic grains; The stomata are distributed in strips in the spatial distribution; and the content of Zn in the two alloys is different, which resulting in a large difference in mechanical properties; when the material composition is 2024(25%)/7055(75%), the mechanical properties are the best and the material loss rate is the lowest.