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线性摩擦焊IN718接头微观组织与织构演变

Investigation on microstructure and texture evolution of linear friction welded IN718 superalloy joints

  • 摘要: 不同工艺参数下对IN718高温合金进行了线性摩擦焊接试验,采用OM,SEM,EBSD等对接头微观组织与织构进行了表征.结果表明,在摩擦压力169 MPa、振幅3 mm、频率35 Hz、摩擦时间6 s参数组合下获得的接头质量相对较好,但在焊缝端部仍能发现氧化物和碳化物.焊缝区δ相完全溶解,残留少量NbN;而热力影响区δ相部分溶解,部分晶界发生液化并伴有Laves相的产生.焊缝区发生了充分动态再结晶,呈现为等轴细晶组织,并在剪切力的作用下出现了明显剪切织构C(100)011,而热力影响区发生部分动态再结晶,形成了(335)186织构.

     

    Abstract: Linear friction welding tests under different process parameters were performed on IN718 Ni-based superalloy. The microstructure and texture of the joint was characterized by using OM, SEM and EBSD. The results show that a better joint could be obtained with the parameters of friction pressure of 169MPa, amplitude of 3mm, frequency of 35Hz and friction time of 6s, but oxides and carbides are still presented in the root of the flash. The δ phase in the weld zone has been completely dissolved, just with a small amount of NbN, while the δ phase in the heat-affected zone has been partly dissolved with some liquefied grain boundaries, which results in the formation of Laves phase. The full dynamic recrystallization occurs in the weld zone with the fine equiaxed grains, and a shear texture C was formed under the shear stress, while partial dynamic recrystallization occurs in the thermomechanically affected zone, which induced the formation of texture of (335)I86.

     

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