电子束熔丝沉积快速成形2319铝合金的微观组织与力学性能EI北大核心CSCD

选用直径2 mm的2319铝合金丝材进行电子束熔丝沉积快速成形,制备出尺寸为150 mm×35 mm×52 mm的打印样品。研究了样品在不同方向上的微观组织与力学性能。结果表明,通过控制电子束增材制造的参数,可获得致密无宏观缺陷的块体材料,其致密度可达到99.3%。打印态2319铝合金的平均晶粒尺寸小于10 mm,并含有初晶Al2Cu相、细小析出相和粗大杂质相。样品中存在少量的微小孔洞,其尺寸为5～15 mm。样品在长、宽、高3个方向的拉伸强度分别约为161、174和167 MPa。经T6处理后,粗大相基本熔解,析出尺寸更细小、分布更均匀的沉淀强化相,孔洞尺寸有所增大。由于沉淀强化起了主导作用,T6处理后样品力学性能显著提高,3个方向的拉伸强度分别提高到约423、495和421 MPa。

Microstructure and Mechanical Properties of Additive Manufactured 2319 Alloy by Electron Beam Freeform Fabrication

Aluminum alloys have the advantages of light weight and high strength, and they are important structural materials in aerospace field. The additive manufacturing technology of aluminum alloys has a potential application prospect in the field of on-orbit manufacturing in the future, and the technology of electron beam fuse deposition is the best process selection due to its unique technical advantages. In the present study, 2319 aluminum alloy wires with diameter of 2 mm were used for additive manufacturing (AM) by electron beam freeform fabrication (EBF3), with a sample of 150 mm x 35 mm x 52 mm being printed. The microstructure and mechanical properties of the printed sample in three directions were investigated. The results showed that bulk materials of the 2319 alloy can be printed without macroscopic defects under selective EBF3 parameters, with a relative density of 99.3% compared to the initial wires. The average grain size of the printed sample was less than 10 mm, containing primary Al2Cu phases, fine particles, and coarse impurity phases. There are some tiny voids in the printed sample, and the sizes of the voids are 5 similar to 15 mm. The ultimate tensile strengths of the printed sample were 161, 174 and 167 MPa in the length, width and height directions. After a T6 treatment, the coarse phase were basically dissolved and some finer phases were re-precipitated. Due to the dominant effect of dispersion strengthening, the mechanical properties of the sample were significantly improved, and the ultimate tensile strengths of the sample in three directions were increased to 423, 495, and 421 MPa, respectively.