电磁搅拌对激光熔凝TA15钛合金熔池凝固研究

发布时间：2019-02-15 00:02

【摘要】：为了研究电磁搅拌作用对激光熔凝熔池凝固过程的影响,采用有限体积法对施加磁场前后激光单道动态熔凝TA15钛合金过程进行三维磁-热耦合数值模拟。研究了磁场对激光熔池流场、熔凝单道及其周边基材温度分布、固液界面处温度梯度和凝固速度的影响,并采用试验手段对模拟结果进行了验证。模拟结果表明:电磁搅拌作用使激光熔池最大流速增加了约20%,对流加剧促进了熔池热交换作用,使其最高温度下降,固液分界面处温度梯度大幅降低,凝固速度小幅增大,从而有利于熔池顶部组织发生柱状晶-等轴晶转变(CET)。试验结果显示施加磁场后熔凝层顶部有等轴晶组织生成,且随着远离磁场中心,电磁力增大,等轴晶区有扩大趋势。试验结果和模拟结果一致性较好。
[Abstract]:In order to study the effect of electromagnetic stirring on the solidification process of laser melting pool, the 3-D magneto-thermal coupling numerical simulation of laser single channel dynamic melting of TA15 titanium alloy before and after the application of magnetic field was carried out by finite volume method. The effects of magnetic field on the flow field of the laser melting pool, the temperature distribution of the single channel and its surrounding substrate, the temperature gradient at the solid-liquid interface and the solidification velocity are studied. The simulation results are verified by means of experiments. The simulation results show that electromagnetic stirring increases the maximum flow velocity of the laser molten pool by about 20 percent, and the convection accelerates the heat exchange in the molten pool, which decreases the maximum temperature, decreases the temperature gradient at the solid-liquid interface, and increases the solidification velocity slightly. Thus, it is advantageous to columnar crystal equiaxed crystal transition (CET). In the top microstructure of molten pool. The experimental results show that equiaxed crystal structure is formed at the top of the melting layer after the application of magnetic field, and the electromagnetic force increases with the distance from the center of the magnetic field, and the equiaxed crystal region tends to expand. The experimental results are in good agreement with the simulation results.
【作者单位】：沈阳航空航天大学航空制造工艺数字化国防重点学科实验室;
【基金】：国家自然科学基金(51505301,51305280,51375316) 辽宁省自然科学基金(2015020118)
【分类号】：TG292

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