沈盟凯 董太宁 葛鸿浩 石新升 张群莉 刘云峰 姚建华. 316L激光粉末床熔覆IN718偏析带形成过程的模拟[J]. 金属学报, 10.11900/0412.1961.2023.00422.

摘要 相关文章 Metrics 全文: PDF(1452 KB)   摘要: 异种金属在激光熔覆、焊接等热加工成型过程中易出现偏析带，偏析带常与凝固裂纹伴生，直接影响加工成型后的力学性能。为了研究异种金属材料冶金结合时偏析带形成机制及其演化规律，本工作将元胞自动机方法和Eulerian多相流算法相结合，建立了在316L不锈钢上激光熔覆IN718合金的二维熔化凝固模型，系统研究了激光熔覆过程中的温度场、熔池形貌、熔体流动以及元素分布的演化过程。通过对比熔池几何尺寸和晶粒取向验证了模型的合理性，对比x方向和y方向上的Fe元素含量分布来验证模型的可靠性。模拟结果表明，316L不锈钢基板上激光熔覆IN718合金冶金结合过程中出现了Fe、Ni元素富集、贫瘠交替分布的偏析带，与实验结果吻合较好。通过分析熔池中Fe元素的分布、熔池形貌和熔体流态的演化过程，该偏析带是熔池凝固过程中流体流动与熔池形貌变化不协调的结果。 关键词 ： 偏析带,  数值模拟,  元胞自动机,  元素分布     Abstract：During laser cladding, welding, and other hot forming processes, dissimilar metals can form segregation bands. These bands often lead to solidification cracks that can directly affect the mechanical properties of the processed and formed materials. To study the formation mechanism and evolution of segregation bands during metallurgical bonding of dissimilar metal materials, we used a two-dimensional melting and solidification model for laser cladding of IN718 on 316L stainless steel. This model was established using the cellular automata method and Eulerian multiphase flow algorithm. Our research comprehensively analyzed the evolution of the temperature field, molten pool morphology, melt flow, and elemental distributions during laser cladding. We confirmed the rationality of the model by comparing the melt pool geometry and grain orientation. Additionally, we confirmed reliability of the model by comparing the distribution of elemental iron content in the x- and y-directions. Simulation results indicate that the Marangoni force drives more iron elements from the bottom of the melt pool (substrate) to the rear end of the melt pool, increasing the temperature of the liquidus at that location. This solidification promotion at the rear end of the melt pool causes actual solidification liquidus temperature (Ta) to be biased toward substrate liquidus temperature (Tb), resulting in the formation of a region with a high concentration of iron elements. The rear end of the melt pool takes on a “bulging” shape, increasing the melt flow rate within the pool. This increase rolls more iron elements from the front end of the melt pool (powder) to the rear end of the pool. Consequently, the liquidus temperature at the rear end of the melt pool decreases, biasing Ta toward the liquidus temperature of the powder (Tp). This process hinders solidification at the rear end of the melt pool, resulting in the formation of a region with a reduced concentration of iron elements. The rear end of the melt pool flattens gradually, decreasing the melt flow rate and drawing more elements from the front to the rear end. This change results in the formation of a segregation zone with an alternating distribution of high and low elemental iron content, which is consistent with the experimental results. The rate at which the solid–liquid interface moves can be calculated by finding the difference in the solute concentration between the interface neighboring cells. Fluctuations in the molten pool flow cause the morphology of the rear end of the molten pool to constantly change, resulting in varying concentrations of elemental iron after solidification. Therefore, increasing the homogeneity of element mixing in the molten pool can reduce the degree of segregation. During the experimental process, appropriate increase in the laser power and scanning rate reduction can improve the quality of the cladding layer. Key words： segregation zone    numerical simulation    cellular automata    distribution of element 收稿日期: 2023-10-25      ZTFLH:  TG174.4   基金资助:国家自然科学基金重点项目;浙江省自然科学基金重大项目;浙江省“领雁”研发公关计划项目 服务 把本文推荐给朋友 加入引用管理器 E-mail Alert RSS 作者相关文章 沈盟凯 董太宁 葛鸿浩 石新升 张群莉 刘云峰 姚建华 44.8K 链接本文: https://www.ams.org.cn/CN/Y0/V/I/0 [1] 毕中南, 秦海龙, 刘沛, 史松宜, 谢锦丽, 张继. 高温合金锻件残余应力量化表征及控制技术研究进展[J]. 金属学报, 2023, 59(9): 1144-1158. [2] 王重阳, 韩世伟, 谢峰, 胡龙, 邓德安. 固态相变和软化效应对超高强钢焊接残余应力的影响[J]. 金属学报, 2023, 59(12): 1613-1623. [3] 张开元, 董文超, 赵栋, 李世键, 陆善平. 固态相变对Fe-Co-Ni超高强度钢长臂梁构件焊接-淬火过程应力和变形的影响[J]. 金属学报, 2023, 59(12): 1633-1643. [4] 陈学双, 黄兴民, 刘俊杰, 吕超, 张娟. 一种含富锰偏析带的热轧临界退火中锰钢的组织调控及强化机制[J]. 金属学报, 2023, 59(11): 1448-1456. [5] 周小宾, 赵占山, 汪万行, 徐建国, 岳强. 渣-金界面气泡夹带行为数值物理模拟[J]. 金属学报, 2023, 59(11): 1523-1532. [6] 夏大海, 邓成满, 陈子光, 李天书, 胡文彬. 金属材料局部腐蚀损伤过程的近场动力学模拟：进展与挑战[J]. 金属学报, 2022, 58(9): 1093-1107. [7] 胡龙, 王义峰, 李索, 张超华, 邓德安. 基于SH-CCT图的Q345钢焊接接头组织与硬度预测方法研究[J]. 金属学报, 2021, 57(8): 1073-1086. 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