非均匀温度场Fe-0.06%C合金焊接接头凝固过程模拟分析

发布时间：2018-06-20 01:34

本文选题：焊接冶金 + 数值模拟　；参考：《材料科学与工艺》2015年01期

【摘要】：利用元胞自动机和有限差分(CA-FD)法,采用宏-微观两种尺度,将宏观温度场与微观枝晶生长过程耦合在一起,再现了Fe-0.06%C二元合金焊接熔池的凝固过程.同时,探讨了边界散热速率对焊接熔池中枝晶生长形貌及晶粒尺寸的影响;分析了形核基底数与枝晶生长间的关系;并用实验对模拟结果进行了验证.结果表明,在熔池凝固过程中,温度梯度沿散热边界向绝热边界方向不断减小,等温线弧度不断增大;熔池散热边界附近的液相中溶质浓度远远高于绝热边附近和模拟区域中心的液相溶质浓度;模拟区域内的温度梯度随着边界散热速率的增大而升高.此外,随着形核基底的增加,柱状晶数量基本不变;而等轴晶数量不断增多,分布范围逐渐扩大,但尺寸有所减小.模拟结果反映了焊接熔池的凝固过程,并与实验结果吻合,为实际焊接工艺的选取提供了一定的参考.
[Abstract]:By using the cellular automata and the finite difference (CA-FD) method, the macro and micro two scales are used to combine the macro temperature field with the microdendritic growth process, and the solidification process of the welding pool of the Fe-0.06%C two element alloy is reproduced. Meanwhile, the influence of the boundary heat dissipation rate on the dendrite growth morphology and grain size in the weld pool is discussed. The relationship between the number of nucleation base and the growth of dendrite, and the results of the simulation are verified by experiments. The results show that the temperature gradient decreases along the heat dissipation boundary in the adiabatic boundary, and the arc of the isotherm increases continuously during the solidification process of the molten pool, and the solute concentration in the liquid phase near the heat dissipation boundary of the molten pool is far higher than that near the adiabatic edge and the simulation. The concentration of liquid solute in the center of the region; the temperature gradient in the simulated region increases with the increase of the boundary heat dissipation rate. In addition, with the increase of the nucleation base, the number of columnar crystals is basically unchanged, while the number of equiaxed grains increases, the distribution range expands gradually, but the size decreases. The simulation results reflect the solidification process of the weld pool. It is consistent with the experimental results, and provides a reference for the selection of actual welding process.
【作者单位】：西安理工大学材料科学与工程学院;
【基金】：国家自然科学基金资助项目(51274162) 国家高技术研究发展计划资助项目(863计划)(2013AA031303) 陕西省基础研究计划项目(2012JM6003)
【分类号】：TG407

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