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利用Ansys有限元软件进行数值模拟并利用光纤激光器进行试验验证。分别采用蔡司显微镜、电化学工作站研究熔凝表面的微观组织和腐蚀行为。结果表明:激光熔凝温度场呈骤热快冷、动态变化的特点,其表面的温度梯度最大,由表及里,温度梯度依次减小。实际测量与数值模拟的熔池深度和熔池宽度的误差均不超过15%,表明温度场数值模型与实际模型相符合。激光熔凝后,稀土镁合金材料表层晶粒细化,其自腐蚀电流密度较母材降低了一个数量级,表明激光熔凝可有效改善稀土镁合金材料表面的耐蚀性。
Ansys finite element software was used to simulate and verify with fiber laser. Zeiss microscopy and electrochemical workstation were used to study the microstructure and corrosion behavior of the fused surface. The results show that the temperature field of laser melting is characterized by sudden rapid cooling and dynamic change. The temperature gradient of the surface is the largest, and the temperature gradient of the surface and the temperature decreases in sequence. The error between the measured depth and the width of the weld pool did not exceed 15% in actual measurements and numerical simulations, indicating that the numerical model of the temperature field is in accordance with the actual model. After laser melting, the grain size of the surface of rare earth magnesium alloy is refined and its self-corrosion current density is reduced by one order of magnitude compared with the base metal. It shows that laser melting can effectively improve the corrosion resistance of the surface of rare earth magnesium alloy.