Abstract
An extremely high-strength TiAl/Ni-based superalloy dissimilar joint was obtained using a designed Ni25Zr25Sn20Cu10Hf10Cr5Fe5 multi-principal element interlayer via contact reaction brazing.It was found that a joint mainly composed of eutectic structure of(Ni)ss,(Ni,Cr,Fe)ss,and(Cr,Ni,Fe,Mo)ss,as well as micro-nano precipitates of(Ti)ss and(Hf,Zr)ss,could be achieved through the interaction between the interlayer and the base metals.The joint exhibited a shear strength of 498 MPa when brazed at 1190℃ for 10 min,while the fracture occurred within the TiAl base metal,and the retention rate of high-temperature(HT)strength(650 ℃)was～100％.The strengthening mechanism of the brazed joint was systematically discussed by transmission electron microscopy(TEM).It was shown that high-density dis-locations existed in each phase of the seam as well as twinning and stacking faults existed in the micro-nano precipitates,caused by a mass of solute atoms,greatly strengthened the joint.At HTs,the dislocation strengthening effect weakened due to grain recovery and recrystallization,but the joint could be addi-tionally toughened by multi-cracking.Meanwhile,granular(Ti)ss dispersed through the seam and ductile reticular structure(Ni)ss toughened the joint via the mechanism of crack termination and bridging.The proposed method provides a new approach for high strength and heat resistance joining of TiAl/Ni-based superalloy in aeroengine components.
基金项目
National Natural Science Foundation of China(NSFC)(51974101)
National Natural Science Foundation of China(NSFC)(51975150)
National Natural Science Foundation of China(NSFC)(U21A20128)
National Natural Science Foundation of China(NSFC)(52175302)
National Natural Science Foundation of China(NSFC)(U22A20185)
National MCF Energy R&D Program(2019YFE03100100)
Fundamental Research Funds for the Central Universities(2022FRFK060009)
Fundamental Research Funds for the Central Universities(HIT.DZJJ.2023011)
Natural Science Foundation of Heilongjiang Province,China(JQ2020E003)
NETL
NSTL
万方数据