电-磁复合场协同作用对激光熔覆层组织的调控机理研究

项目名称： 电-磁复合场协同作用对激光熔覆层组织的调控机理研究

项目编号： No.51475429

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 姚建华

作者单位： 浙江工业大学

项目金额： 83万元

中文摘要： 现有的激光熔覆难以实现对熔覆层组织和性能的差异化定制。本项目提出了利用电场和磁场的复合场协同作用，利用在熔池内形成的可驱动、抑制或偏转对流的电磁力（洛伦兹力），改变连续熔覆过程中的传热传质行为，实现对熔覆层组织的选区定向调控，可获得具有生长方向和性能趋向性的组织、外加溶质元素或硬质相的分布控制，减少或消除熔覆层中的常见缺陷，克服单一强磁场影响下作用效率低、无法控制熔池流体的趋向性等难题。本项目将建立电-磁复合场协同激光熔覆过程中的多物理量耦合模型，揭示不同类型洛伦兹力对熔池对流的影响规律，获得熔池对流状态的趋向性变化与熔覆层晶粒形态、大小和生长取向之间的关系。本项目成果有望应用于高温涡轮机等关键部件，通过局部选区微观组织定向制造实现性能差异化定制，进一步优化零件的组织与性能，本项目理论与方法不仅可用于激光熔覆技术，还可拓展至激光增材制造、激光焊接及激光合金化等其他激光加工领域。

中文关键词： 激光熔覆；组织；电-磁复合场；洛伦兹力

英文摘要： The traditional regulation of laser process parameters could only change the thermal boundary of laser cladding melt pool, but difficult to control the direction of the fluid and the diversity of microstructure and performance. Therefore, the synergistic effect of composite field containing electric field and magnetic field were proposed by our group. Due to the synergistic effect, the Lorenz force was formed to drive, suppress or bias the melt flow，influencing the heat and mass transfer, controlling the microstructure of cladding layer. With the different types of synergistic effect, the directional growth crystal could be obtained, the defects in the cladding layer could be decreased and the gradient distribution of the solute element or hard phase could be realized. The multi-physics model including electric-magnetic synergistic effect during the processing of laser cladding would be created. The relationship between Lorenz force and melt flow would be explained, the mechanism of the shape, size and growth orientation of microstructure accompanying with the changes of convection would be exhibited. Meanwhile, the research results can be extended to the laser additive manufacture, laser welding, laser alloying and other laser processing fields.

英文关键词： laser cladding;microstructure;electric-magnetic synergistic effect;Lorenz force