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Scanning electron beam surface alloying can effectively improve the surface properties of metal samples. After tungsten alloying treatment on the surface of 45 steel by scanning electron beam, a strengthened layer consisting of alloying zone and heat-affected zone was formed on the surface. The microstructure in alloying zone is acicular martensite and columnar crystal, the microstructure in heat affected zone is acicular martensite and ferrite, and the matrix microstructure is ferrite and pearlite. With the increase of electron beam power, the columnar crystal content in alloying zone increases, the acicular martensite content in heat affected zone increases and the ferrite content decreases. The thickness of alloy zone and heat affected zone increases nonlinearly, and the surface hardness increases gradually. The maximum hardness of the sample surface is 1170HV, which is more than 5 times that of the matrix.

The surface WC/Ni-Co based alloying treatment of 30CrMnSi steel was carried out using scanning electron beam technology, and the tissue distribution after alloying were tested and investigated. The results show that the cross-section of the alloyed specimen consists of three parts: the alloy layer, the heat affected zone and the substrate. The thickness of the alloy layer was increased by 18.3 μm compared to the thickness of the pre-coated layer. The alloy layer is organised in a composite gradient, consisting of martensite and ledeburite with carbides.

The surface alloying of scanning electron beam can improve the microstructure and mechanical properties of steel materials. In this paper, Cr/Ni alloying treatment was performed on 35CrMo alloy structure steel by using continuous scanning electron beam to improve surface performance. The influence of scanning electron beam technology on the structure of alloy layer is studied, and the influence of coating thickness on the structure and properties of the alloying layer is discussed. The results show that the surface of 35CrMo steel is composed of alloying layer, heat affected zone and matrix. The microstructure of the alloying layer is short columnar crystal, equiaxed crystal and acicular martensite. The surface hardness can reach 770HVwhen the coating thickness is 5μm, which is 2 times of the matrix. With the increase of Cr/Ni coating thickness, the surface of sample hardness decreases, and the corrosion resistance of the sample increases.

Aiming at the problem that it is difficult to identify the fast moving objects in complex background, the paper proposes a method that establishes the inter-frame background sequence, and then multiply the pixel grayscale in the difference image. It defines constraint rules for public background image, gets moving target region with higher-order cumulant and block grayscale, and further highlights the edges of moving objects, largely eliminating the natural environment noise from lighting, scene and shooting angle changes. Experimental results show that this method can maintain real-time tracking of moving objects, identify non-overlapping moving targets, and provide the basis for subsequent target analysis.