关键词: 2219铝合金, 腐蚀损伤, 应力水平, 暴露时间, 力学性能

Abstract: In order to identify the effect of stress level and exposure duration on corrosion damage mechanical properties of 2219 aluminum alloy, some specimens exposed to EXCO corrosion solution under different stress levels and accelerated corrosion at different duration were selected to carry out surface pit depth measurement, mechanical properties testing and tensile fracture morphology observation. The test results show that both stress level and exposure duration are important factors affecting the development of stress corrosion damage thus affecting the change of mechanical properties of the material. At the initial stage of corrosion, i.e. before 1.5 h, the effect of stress level is limited. When the exposure duration reaches 2.0 h or more, the corrosion damage characterized by the average depth of pits caused by stress level is more significant. However, within the test time (2.5 h), the effect of stress level on corrosion damage is less than that of exposure duration, so the effect on the change of mechanical properties of materials is also less than that of exposure duration. Pits and microcracks caused by corrosion damage destroy the continuity of the material and decrease the mechanical properties of it, such as tensile strength, elongation and modulus of elasticity, which is an important reason for the instantaneous fracture of the material without sufficient plastic deformation stage in the tensile test. A larger pit or a deeper microcrack may be the origin of the main crack in the fracture surface.

Key words: 2219 aluminum alloy, corrosion damage, stress level, exposure duration, mechanical properties