High-strength and tough ZL205A aluminum alloy, with its excellent mechanical properties, has broad application prospects in military and aerospace fields. However, its poor casting performance often leads to localized casting defects in castings, necessitating welding repairs. During the welding repair process, welding heat cracks that meet strict engineering requirements are prone to occur and are extremely difficult to eliminate. The formation of welding
heat crack defects is related to factors such as welding methods and processes, but more importantly, the crack resistance of the welding wire material used plays a decisive role in preventing welding heat cracks. So far, there have been no reports on research regarding the welding repair of ZL205A alloy castings. The welding wires used for repairs are generally prepared from the base material, with various manufacturers either directly cutting strips or producing strip or coil forms based on their specific conditions, resulting in poor crack resistance. There is an urgent need to develop a new type of crack-resistant welding wire to improve this situation. This paper draws on research methods for welding wires of wrought aluminum alloys and, based on the characteristics of ZL205A alloy, aims to reduce the hot cracking susceptibility of the welding wire material by optimizing the composition ratio of the base welding wire material and adding trace alloy elements, thereby achieving the goal of mitigating welding heat crack defects.
Some research data suggest that the three elements Cu, V, and Zr have a significant impact on the hot cracking susceptibility of Al-Cu type alloys. Through orthogonal experiments on these three elements, it was found that adjusting the alloy element composition ratio within the range of the base welding wire material has little effect on reducing the hot cracking susceptibility of the welding wire material, possibly due to the complexity of the alloy composition and the narrow composition range, where minor adjustments fail to achieve the desired results. In the study of adding trace rare earth elements, it was found that both Ce and La can reduce the alloy's hot cracking tendency, but the effect of Ce is not significant, with a long incubation period, and it also reduces the fluidity of the alloy to some extent. When La is added in the form of pure metal, the results are unstable; when added in the form of a master alloy, the effect is good, and the optimal addition amount was determined through experiments to be 0.2%. Metallographic analysis revealed that the addition of La refines the alloy grains, thereby significantly improving the alloy's crack resistance. The traditional welding wire preparation process is: melting—ingot casting—extrusion—drawing. Since this process generally requires large-scale preparation, it can easily lead to poor microstructure in the preformed ingots during melting and ingot casting, resulting in low yield rates and affecting the quality of the prepared welding wire. This study adopted a new preparation process: melting the alloy with a given ratio—continuous casting to produce 10mm diameter rods—drawing—surface treatment. The alloy is directly quenched from liquid to 10mm diameter rods, resulting in a dense and fine microstructure and correspondingly improved yield rates. Advanced surface treatment technology was used, and the final welding wire obtained was ideal. Finally, in comparative welding repair tests with base welding wires, it was found that the improved welding wire significantly reduced the alloy's hot cracking susceptibility, achieving the goal of reducing heat crack defects in the welding repair areas of castings.

• ?Main Components?：
  • ?Aluminum (Al)?：The main component of ZL205A is aluminum, with its content being the remainder?1.
  • ?Copper (Cu)?：Content ranges between 4.6% and 5.3%?1.
  • ?Magnesium (Mg)?：Content ranges between 0.15% and 0.35%?1.
  • ?Titanium (Ti)?：Content ranges between 0.15% and 0.35%?1.
  • ?Cadmium (Cd)?：Content ranges between 0.15% and 0.25%?1.
  • ?Iron (Fe)?、?Manganese (Mn)?、?Nickel (Ni)?、?Tin (Sn)?、?Chromium (Cr)?、?Silicon (Si)? and other elements have limited contents, with specific values not clearly provided in the search results?1.

These components collectively determine the physical and chemical properties of ZL205A, making it excel in specific applications. For example, ZL205A aluminum alloy has good casting performance and mechanical properties, making it suitable for various industrial applications, including aerospace and automotive manufacturing?