| Magnesium alloy, the green engineering material in 21st century, has gradually become an important material applying to the army, navy and air force traffic carrying equipment based on its advantages of lightness, high strength, rich mineral resources and easily-recycled. However, its resistance to corrosion and wear is relatively poor, which, to a certain degree, limits the wide application of magnesium alloys. So the surface modification technology to improve its corrosion and abrasion resistance and other properties is bestowed on the great practical significance.Taking AZ31B magnesium alloy as the research object and laser remelting technology as the method, this paper adopts the 3kW semiconductor laser processing system in order to enhance the abrasion and corrosion resistance of the alloy. The infrared thermal imager is used to measure the distribution and change of the temperature field in the process of laser remelting, which is then compared with ANSYS numerical simulation. This paper uses optical microscopy (OM), X-ray diffraction (XRD) and electrochemical corrosion equipment to study the influence of laser processing parameters on the remelting layer organization and its performance, and makes a comparative analysis of the original magnesium alloys and the surface modification layer, respectively from the aspect of microstructure, phase, electrochemical corrosion performance and abrasion performance,and make a numerical simulation of laser remelting layer temperature field by using ANSYS method.After laser-remelting treatment of the AZ31B magnesium alloys, the laser remelting layer and the base coagulate nicely, with no cracks, no pores and other blemishes. The remelting layer of magnesium alloy is analyzed respectively by changing the laser power and scanning velocity these two parameters. It's found that with the increase of laser power or the decrease of scanning velocity, the remelting width and depth will be both increasing accordingly. Magnesium remelting layer is composed byα-Mg andβ-Mg17Al12, apparently finer than the substrate, and the corrosion stability and abrasion resistance are both improved. The corrosion potential moves up by 0.076～0.152V, and corrosion current density lowers one order of magnitude.In this paper the infrared thermograph is used to monitor the semiconductor laser and AZ31B magnesium alloys temperature field in real-time, and with the help of the finite element numerical simulation software ANSYS to simulate the temperature feature. The comparative analysis shows that the temperature results in the simulation are much closer to experimental test results. So ANSYS simulation can completely replace the experimental test.This paper develops the analysis procedure of temperature field in the remelting process by using secondary development language APDL in finite element, and automates the simulation process, and studies the dynamic process of temperature field and its distribution at a given laser parameters and the rule of its influence on layer depth and width.This technology establishes the laser broadband heat-source model applicable to the laser remelting process, and applies ANSYS 11.0 software to establish the light-spot model in the remelting process. Considering the nonlinear relationship between thermal physical property parameters of the material and the temperature, and the initial and boundary conditions, this paper makes an analysis of the laser remelting temperature field. The remelting test of AZ31B magnesium alloy plates shows that the shape formed in broadband heat-source model and the section topography in pan-shaped remelting zone both conform to the actual data. Remelting zone section size is consistent with the testing value, which validates the accuracy and applicability of the model.Through the comparison of simulating data, experimental data and corresponding graph, it's found that a closer temperature field can be built by using ANSYS simulating laser remelting technology. A proper laser spot and remelting zone section can be calculated by using broadband heat-source model, and more reasonable temperature field distribution can be obtained. All these are of great practical significance.
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