Comparative Studies of the Properties of Heat-Treated Welded Joints of AA2219 Alloy

Abstract

Comparative studies of welded joints of AA2219 alloy after corrosion tests in amyl (which is used as rocket fuel) are carried out. No changes in the morphology and dimensions of structural parameters in metal of seams and in heataffected zone are revealed after exposure in amyl. Corrosion resistance of the AA2219-T81 and AA2219-T62 alloys in amyl corresponds to the standard metal resistance group-'resistant'. Welded joints are also resistant against intergranular and exfoliating corrosion as well as corrosion cracking: no local corrosion defects are detected. Strength coefficient of AA2219-T62 welded joints is by 30% higher than for AA2219-T81 joints, and, for both types, it is equal to 0.96 and 0.65, respectively. After soaking in amyl, T62 joints have higher ultimate strength and yield stress compared to T81 ones. Strength coefficient of AA2219-T62 welded joint after corrosion tests remains higher (0.94) than the strength coefficient of AA2219-T81 welded joint (0.65). At the same time, decrease in relative elongation of both joints may point to embrittlement of structural components in corrosive environment. As established, the heat-treatment conditions do not affect the values of resistance against uniform and local corrosion, mechanical strength and plasticity of the base metal. However, for welded joints, strength and plasticity are affected by heat-treatment conditions: AA2219-T62 joints have more uniform structure