激光修复GH4169合金中Laves相的电磁控制及相转变机理

During the repairing of GH4169 superalloy damaged work piece, Laves phase will remain in the repaired zone for no high temperature solution treatment is allowed to the repaired work piece in order to reducing the influence to microstructure and dimension of the original work piece, and this results in the worse matching of strength and plasticity of the repaired work piece. This program use the electromagnetic stirring method to the molten pool during laser repairing aiming to achieve the improvement of its matching of strength and plasticity. The effects of magnetic field intensity and laser scanning speed on precipitation of Laves phase, micro segregation of alloying elements will be studied by the investigation on precipitation behavior of Laves phase. The nucleation mechanism of delta phase around the Laves phase and its growing behavior, as well as the homogeneity of alloying elements and microstructure, will be analyzed through the phase transformation mechanism of Laves phase to delta phase during heat treatment. The cooperative strengthening effect of Laves phase and γ″ phase for the repaired zone will be explained by the investigation of precipitation regularity of γ″ phase in condition of Laves phase existing and the deformation behavior of repaired work pieces under loading. Supports of laser repairing in damaged work pieces of aeronautics and astronautics industries and national defense industries will be applied by this research.

针对激光修复GH4169镍基高温合金修复区中Laves相无法通过高温固溶处理去除并对零件整体组织和力学性能造程强塑性失配的难题，拟采取对熔池施加电磁搅拌实现修复区Laves相形貌和体积分数的控制。通过电磁场中Laves相析出机制分析，明晰磁场强度、激光修复工艺参数（激光功率、扫描速率等）等对修复区Laves相形析出行为、合金元素微观偏析行为的影响；通过Laves到delta相转变机理分析，获得修复区Laves相周围delta相形核和长大规律及此过程在修复区组织和元素均匀化过程的影响中的作用；通过Laves相对激光修复GH4169合金γ″相析出规律及其强化机理分析，获得Laves相与γ″相同存在情况下修复区金属的强化机理，实现合金高性能修复。项目的实施可为激光修复技术在航空发动机零件及其他部件修复中的应用提供依据。

项目针对激光修复GH4169镍基高温合金修复区中Laves相无法通过高温固溶处理去除保留在修复材料中，并对零件整体组织和力学性能造程强塑性失配的难题，采取对熔池施加电磁搅拌实现修复区Laves相形貌和体积分数的控制，减小修复区域母材组织及合金元素分布的不一致，促进γ″相充分析出，实现修复区和母材强度和塑性的匹配性。.项目实施过程中设计制造了具有电磁搅拌辅助功能的激光修复用送粉喷嘴，开发了专用电源系统，结合机器人控制技术完成了电磁辅助激光增材和修复系统。对电磁场作用下激光熔池的流动行为、熔池和温度重新分布规律、熔池凝固行为、枝晶生长规律和Laves相析出机制、合金元素偏析行为、Laves 相转变形核机制、相长大机制以及热力学动力学规律、转变过程中修复区组织和元素均匀化规律、Laves相存在情况下激光修复GH4169合金γ″相析出规律及合金强化机理等内容展开了深入研究，完成了项目预定的所有研究内容。通过研究，项目厘清了电磁辅助激光修复GH4169合金脆性相析出和溶解规律，获得了Laves 相转变机制，揭示了Laves相与γ″相共存下的合金强化机理，为激光修复技术在航空发动机关键零部件修复中的应用提供依据。.项目按计划完成了所有研究内容，获得了丰富的研究实验数据和成果。项目计划在4年内完成“激光修复GH4169合金中Laves相的电磁控制及相转变机理”研究。项目在规定时间内完成了预定研究计划，研究成果共发表学术论文31篇，授权专利7项，获得省部级科研奖励5项，培养毕业硕士研究生11人。