2219铝合金不同气氛下TIG焊焊接接头组织性能

为研究氦弧TIG焊焊缝质量，对比分析了2219铝合金氦弧TIG焊与氩弧TIG焊焊缝成形及组织性能.结果表明，在背部熔宽相同的条件下，氦弧TIG焊焊缝正面熔宽、下塌量及热影响区宽度均小于氩弧TIG焊，氦弧TIG焊与氩弧TIG焊焊缝的微观组织及第二相组织基本相似，焊缝区晶粒为等轴晶，热影响区晶粒为粗大的板条状，组织为粗大的α铝基体与金属间化合物Al₂Cu及少量的共晶组织，焊缝区的第二相组织明显多于热影响区，无法发挥弥散强化的作用.氦弧TIG焊与氩弧TIG焊焊接接头的断裂方式均为韧性断裂，抗拉强度基本保持一致，氦弧TIG焊焊接接头的断裂总延伸率高于氩弧TIG焊，维氏硬度高于氩弧TIG焊焊缝的硬度.

Microstructure and mechanical properties of 2219 aluminum alloys TIG welding welded joints in different shielding gases

The microstructure and mechanical properties of 2219 aluminum alloys welded joints of helium shielded TIG welding and argon shielded TIG welding were investigated. The results show that, the width of the weld bead, the concavity and the width of heat affected zone in helium shielded TIG welding are smaller than those in argon shielded TIG welding. The microstructure and second-phase of them are similar. The grains in weld area are isometric. In heat affected zone, grain are coarse stripes, and there are the α aluminum substrate, the inter-metallic compound Al₂Cu and some eutectic structure. The amount of the second-phase particles in weld zone is larger than that in heat affected zone. The tensile strength of the welded joints are similar, and the fracture modes are both ductile fracture. The elongation and hardness of the welded joint of helium shielded TIG welding are larger.