中间层对 GH5188 高温合金TLP 扩散焊接头的影响

Through independent research and development, three kinds of amorphous intermediate layers of KCo7, KCo8 and KCo9 with different W contents were prepared, characterized by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC), and verified through vacuum transient liquid phase bonding of GH5188 superalloys at 1180 ℃ for 60 min. The effects of interlayer thickness and interlayer W content on the microstructure and mechanical properties of the joints were investigated separately. The results show that, when the interlayer thickness is 20 μm, the joint exhibits numerous unwelded defects, resulting in room temperature tensile strength of only 568 MPa. However, when the interlayer thickness increases to 40 μm, the weld fills well, forming and the room temperature tensile strength of 941.3 MPa. Additionally, as the W content in the interlayer increases from 0 to 8% (mass fraction), the precipitation of W-rich M₆C in the center of the weld significantly increases, and the room temperature tensile strength initially increases and then decreases. The joints obtained using the KCo8 interlayer with thickness of 40 μm exhibits the highest room temperature tensile strength of 1033 MPa, with fracture occurring in the base material zone.