Effect of joining parameters on mechanical properties of TLP bonded K416B/GH4648 joint reinforced by BCC and γ′ phases

Abstract

In order to address the issues of low seam strength in nickel-based TLP joints, a new Fe-Co-Ni-Al-B multi-component alloy filler was designed. The microstructure of the filler and the microstructure and mechanical properties of TLP joints of GH4648 and K416B using Fe₇(CoNi)₆₃Al₁₄B₁₆ filler were investigated. Furthermore the effects of joining parameters on the microstructure and mechanical properties of the joint were discussed. The results show that the Fe₇(CoNi)₆₃Al₁₄B₁₆ multi-component alloy filler exhibits a dual-phase microstructure consisting of FCC and BCC phases. Precipitated phases within the seam primarily consisted of the matrix FCC phase, BCC phase, M₂₃B₆, Cr-Mo-W boride, and γ′-(Ni, Co)₃Al precipitates on the matrix FCC phase. At a holding temperature of 1160 °C for 120 min, the maximum shear strength of the joint at room temperature and 900 °C is 705 MPa and 380 MPa, respectively. The joints exhibit mixed-mode fracture behavior, characterized by both transcrystalline and intergranular features. The maximum differences in hardness and elastic modulus between the bonding seam and the DAZ are 28.77 GPa and 0.37 GPa, respectively. The microhardness and elastic modulus values of the joint were evenly distributed. This work provides a new idea for the TLP bonding of dissimilar superalloys utilized in the manufacturing of aero-engine turbine guide.