2A12 aluminum plate is a kind of aluminum plate with high hardness and strength, which is widely used in aerospace. As a structural part of aircraft, 2A12 aluminum plate has strict deformation control during machining. The distribution and control of residual stress are one of the problems that need to be solved to ensure the qualified preparation of 2A12 aluminum plate.The structural characteristics of this kind of component are thin wall, changeability and complex stress field including initial internal stress and surface residual stress formed by machining.

The existence of residual stress has two sides:

1. Excessive residual stress harms the dimensional accuracy of the structure, resulting in the unstable shape of the structural parts;

2. Compressive stress can effectively improve the fatigue strength of materials and prolong their service life.For thin-walled parts, reducing and adjusting the surface stress is the key to meet the requirements of qualified preparation and reliable use.The stress acquisition methods can be obtained by lossless and lossy experimental methods, such as X-ray diffraction method, deep hole method and laminar clipping method, as well as finite element simulation technology, which has been widely mentioned in the literature.

Vibration aging is to reduce the residual stress by resonance of the structure or the platform through the action of alternating forces, so that the residual stress region on the member can meet the macro-yield under the condition of excited vibration stress loading.The researchers used the multi-point excitation mode to release the surface residual stress of the high-strength steel plate in combination with the prestressing method, and believed that the VSR could reduce and homogenize the stress, but had limited effect on the deformation adjustment of the structure.The researchers designed a high frequency vibration energy amplifying device to solve the residual stress reduction of small parts in a high frequency, small and large kinetic energy way.The VSR was used to solve the problem of reducing the residual stress on the surface of the expanded bellows.

These studies show that, from the macro point of view, the superposition of the induced vibration stress and the residual stress can produce the desired effect on the structural parts after the macro yield is achieved.On the other hand, through EBSD analysis, it was found that under the aging condition, the surface grains of 2A12 aluminum plate would rotate under the constant amplitude cyclic strain, which was actually the microscopic mode of the deformation of 2A12 aluminum plate and was the main reason for the decrease of stress.In fact, many views believe that VSR can reduce residual stress through micro-yield method, for example, it is found that the dislocation density of the material increases and local hardening, etc. All these indicate that the yield of 2A12 aluminum plate still exists under the VSR even without macro yield.Of course, the selection of vibration aging parameters is very important, and the frequency, time and excitation force all need to be considered in the aging.It has long been believed that the degree of stress reduction is not only related to frequency, but also to amplitude. However, vibration mode and material crystal structure should also be considered, which is equally important for the aging effect of VSR.

This is the end of the analysis of the influence of residual stress on the processing of 2A12 aluminum plate. If you need 2A12 aluminum plate, please contact us.