Abstract
Abstract Monolithic thin-wall components of 2219 Al–Cu alloy are widely used in aerospace and military fields, and usually treated with solution and quenching to improve their comprehensive performance. However, a high magnitude residual stress is introduced into the components during the quenching process, which is unfavorable to the subsequent manufacturing process and service performance. Therefore, residual stress relief is essential to enhance the performance of the components. A conventional effective method is thermal stress relief (TSR). However, the underlying mechanisms of TSR still remain unclear and lack a quantitative interpretation. In the present work, the evolution and distribution laws of the residual stresses, tensile properties, Vickers hardness, dislocations, precipitated phases, and metallography during TSR were investigated. Based on the experimental results, dislocation theory and strengthening mechanisms were applied to reveal the underlying mechanisms of the residual stress relief by TSR. The results showed that the circumferential and axial residual stress relief rates can reach 86.37 and 85.77% after TSR, respectively. The residual stress relief after TSR is attributed to the dynamic evolution of dislocation configuration and density. The improvement in the mechanical properties mainly depends on the precipitated phases and is also affected by the stress orientation effect caused by the residual stress.
Highlights
Due to the excellent high and low-temperature mechanical properties, high fracture toughness, strong stress corrosion resistance, and sound welding performance, the heat-treatable 2219 Al–Cu alloys are widely used in aerospace and military fields [1,2]
Considering that there is a large temperature gradient at the junction between the heating zone and the nonheating zone on both sides of the furnace, the superposition of thermal stress relief (TSR) and vibration stress relief (VSR) is introduced into the large rings to compensate for heat loss, that is, the so-called segmented thermal-vibration stress relief (STVSR)
The research on TSR in this study belongs to general basic scientific research, which can be applied to large and small-size rings or other components, suggesting that the application object and application scope are wider
Summary
Due to the excellent high and low-temperature mechanical properties, high fracture toughness, strong stress corrosion resistance, and sound welding performance, the heat-treatable 2219 Al–Cu alloys are widely used in aerospace and military fields [1,2]. In the subsequent machining process of these components, the balance state of residual stress in the components is broken with the removal of materials, and the residual stress is released and redistributed, causing vulnerable distortion and deteriorating dimensional accuracy, especially for large-scale and complex monolithic thin-walled components with low stiffness [5–7]. This stress affects the static strength, stress corrosion, fatigue resistance, and dimensional stability during the service process, which greatly reduces the service life and safety performance of the components [8–11]. How to effectively predict, control, and reduce the residual stress for improving the comprehensive performance of the components is highly valued in aerospace and other industrial fields
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