## 1 Introduction  
Aerial aluminum alloy is a lightweight structural material widely used in the field of aeronautics and astronautics at present, because of its good comprehensive properties, such as high structural strength, fracture toughness and stress corrosion cracking [1], and usually it is machined using a high speed machining process. Basic data of dynamic mechanical properties of materials is the prerequisite and basis for the simulation of the high speed cutting process and the analysis of the machining mechanism. High temperature dynamic compression tests of 2219 aluminum alloy were carried out by [PERSON] et al. [2], and the deformation characteristics of material and the change rules of flow stress were studied at high temperature. The results showed that 2219 aluminum alloy had high temperature sensitivity, and the flow stress decreased with the increase of temperature. [PERSON] et al. [3] used the Split Hopkinson Tension Bar (SHTB) device to carry out high strain rate dynamic mechanical test of 7075-T6 aluminum alloy at room temperature, and obtained the stress-strain curves of material at high strain rate. [PERSON] et al. [4] studied the dynamic mechanical properties of refractory high-entropy alloys with high plasticity, and the microstructure under different kinds of refractory high-entropy alloys were analyzed by scanning electron microscope (SEM) and other microanalysis methods. Based on the dynamic compression and tensile tests, mechanical properties of some materials had been achieved in initial research results. However, there was a distinct difference between the shear and extrusion forces in the material removal process of high speed cutting.  
Compared with the dynamic compression test, the dynamic shear test data is more accurately to characterize the dynamic mechanical properties of material during the high speed cutting process. The dynamic loading tests of three kinds of AISI D2 steel cap specimens were carried out by the High Split Hopkinson Pressure Bar (SHPB) device by [PERSON] et al. [5], and it was proved that the flow stress and failure strain increased with the decrease of shear band widths. However, because of the complexity of the machining process of cap specimens, the error of specimens preparation directly affected the test results.  
At present, the studies of dynamic mechanical properties of most high strength light alloy materials are based on isotropy theory [6; 7]. However, the matrix, precipitation and microscopical grain of materials had been changed a lot after rolling or other forming processes [8; 9], which showed obvious anisotropic characteristics [10]. Studies on the evolutions of microstructures and textures of 7050 Al alloy plate during solution heat treatment [11] and the influence of texture on dynamic mechanical properties of TC4 rolling plate [12] have shown that the dynamic mechanical properties of metal were different in different forming directions after rolling and other forming processes, especially the rolling direction (RD), transverse direction (TD) and normal direction (ND).  
In this paper, the dynamic shear tests were carried out to analyze the influence of forming directions and strain rate on dynamic shear properties of aeronautical aluminum alloy 7050-T7451, and the main reasons for the anisotropic characteristics of dynamic shear mechanical properties of aluminum alloy 7050-T7451 plate were discussed based on microscopic observation. Based on the effect of forming directions of aeronautic aluminum alloy materials, the dynamic shear property parameters of the materials were obtained, which provided an important basis and premise for building the constitutive model of aeronautical materials considering the direction effect and the reliable analysis of numerical simulation.