Athermal Solidification Research Articles

Microstructural characteristics and mechanical response of transient liquid-phase diffusion bonding AlCoCrFeNi2.1 high entropy alloy utilizing BNi-5 interlayer

This study focuses on the microstructural characteristics and mechanical response of the transient liquid phase (TLP) diffusion-bonded joints of AlCoCrFeNi2.1 high entropy alloy. Bonging parameters were chosen and optimized for the AlCoCrFeNi2.1 alloy and the TLP joining mechanism. The relatively complete isothermal solidification zone (ISZ) ensured a reliable connection of the base metal. As the bonding temperature increased from 1060 °C to 1160 °C, the athermal solidification zone (ASZ) disappeared. The homogenization degree of elements in the ISZ continuously increased, the matrix γ phase became fully ordered, and the B2 phase was precipitated, achieving high entropy state in the ISZ of the joint. Additionally, semi-coherent relationships of [0, 1, 1] L12, [0, 1, 1] B2 and (1, 1̅,1) L12, (2̅, 3, 1̅) B2 were detected between the B2 precipitate phase and the L12 matrix. The phase distribution in the ISZ significantly influenced the mechanical properties of the joint. The complete ordering of the matrix phase at 1160 °C eliminated deformation incoordination between the ISZ and the diffusion-affected zone (DAZ). The B2 phase transitioned from precipitating at the grain boundary at lower temperatures to precipitating uniformly in the ISZ, eliminating the weakening effect of the grain boundary and resulting in tensile strength and elongation comparable to the base material. The fracture morphology indicated a mixed fracture mode.

Transient liquid phase bonding of Hastelloy X to Ni3Al intermetallic compound: Microstructure and phase transformation study

The microstructure of dissimilar transient-liquid-phase (TLP) bonding of Hastelloy X nickel base super alloy to Ni3Al intermetallic by AWS BNi2 filler metal at different temperatures (1000–1150 °C) and time ranges (60–180 min) was investigated. A novel study was done to correlate the phase transformation during bonding with microstructure and phase transformation using field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HR-TEM), and high temperature X-ray diffraction (HTXRD). Efforts were performed to correlate the phase transformation stages during isothermal solidification (IS), formation of Cr-Mo precipitates in diffusion affected zone (DAZ) and dissolution of nickel silicides (eutectic morphology) in athermal solidification zone (ASZ) with their respective reaction temperatures. The high tendency of Hastelloy X to react intensely with filler metal generated Mo-Cr rich phase in DAZ. The ISZ was developed across the joint area after holding at 1100 °C for 180 min. High temperature XRD results on half joint of HX revealed new phases generated at above 1050 °C including BNi2,BNi3, and Ni2Si (Ni-Si eutectic phase) confirmed by FESEM. On the other half joint (Ni3Al), no BNi phases were generated nor nickel silicides by increasing temperature as high as 1150 °C.

Investigation on microstructure and mechanical properties of GH5188 superalloy TLP joints using nickel based alloy interlayer

GH5188 was bonded successfully with a commercial BNi-2 interlayer through transient liquid phase (TLP) diffusion bonding. The characteristic bonded joint was formed by following three characteristic zones: diffusion affected zone (DAZ) mainly consisting of boride precipitates, athermal solidification zone (ASZ) composed of multiple silica-boride phases and isothermal solidification zone (ISZ) containing γ solid solution phases. As the holding time increases, ISZ gradually replaced ASZ and a defect-free joints was obtained then. However, excessive holding time can cause ASZ to reappear because of the extravagant dissolution of the base metal. The joints’ shear strength from 574 MPa (1190 °C/5 min) increased to 777 MPa (1190 °C/60 min), and the fracture location shifted from ASZ to DAZ with the fracture mode transferred from cleavage fracture to mixed fracture.

High-performance brazing of single crystal superalloys with Ni-Cr-Ta filler material

High-performance joining especially brazing has been highly expected in the manufacture or maintenance of single crystal blades. In this paper, a Ni-40Cr-10Ta (at.%) alloy was developed as filler material for single crystal superalloys. High-performance brazing of DD5 superalloy was achieved. The joints brazed at 1260 °C contained an isothermal solidification zone (ISZ) with “γ + γ′” structure and an athermal solidification zone (ASZ) composed of γ, γ', γ/γ′-eutectics, TaCr2 and TaC. Unlike the conventional filler materials with melting point depressants of B and Si, the Ni-Cr-Ta filler material was free of B and Si, and thus the resulting joints contained no B-rich and Si-rich compounds and eutectics with low melting points, which enhanced the brazed joint performance. The tensile strength at 980 ℃ of the heat-treated joints reached 654 MPa, which is 88.5 % that of the base metal.

A 2D and 3D segmentation-based microstructure study on the role of brittle phases in diffusion brazed AISI 304L/NiCrSiFeMoB joints

Nickel-based filler metals are frequently used in high temperature vacuum diffusion brazing for austenitic stainless-steel joints when components are subjected to high static or dynamic loads, corrosive environments and elevated temperatures. Due to melting point depressing metalloids such as silicon and boron, hard and brittle intermetallic phases are formed during the brazing process depending on the diffusion mechanisms. These brittle phases significantly affect mechanical and corrosive properties of the compounds. To quantify the influences of their amount, morphology and distribution, deep learning image segmentation was applied to segment these phases of the athermal solidification zone and the diffusion zone. Subsequently, characteristic microstructure parameters were calculated from these. The parameters of six different brazed joint variations were compared with their experimental characterization of mechanical and corrosive properties so that several correlations could be identified. Finally, a layer-by-layer removal of a brazed joint was performed using a focused ion beam, and a 3D model was reconstructed from the generated images to gain a mechanism-based understanding beyond the previous 2D investigations.

Effect of MBF-20 Interlayer on the Microstructure and Corrosion Behaviour of Inconel 625 Super Alloy after Diffusion Brazing.

The joining zone includes three main parts, which comprise an isothermal solidification zone (ISZ), the athermal solidification zone (ASZ), and a diffusion affected zone (DAZ). Field emission scanning electron microscopy (FESEM) was used here to observe the microstructure equipped with ultra-thin window energy dispersive X-ray spectrometer (EDS) system. Additionally, electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization tests were conducted to evaluate the effect of the DB process on the corrosion resistance of the Inconel 625 superalloy. In the bonding time period, some Mo- and Cr-rich boride precipitations and Ni-rich γ-solid solution phases with hardened alloy elements, such as Mo and Cr, formed in DAZ and ASZ, respectively, because of the inter-diffusion of melting point depressants (MPD). Moreover, during cooling cycles, Ni-Cr-B, Ni-Mo-B, Ni-Si-B, and Ni-Si phase compounds were formed in the ASZ area at 1110-850 °C. The DAZ area developed by borides compound with cubic, needle, and grain boundary morphologies. The corrosion tests indicated that the DB process led to a reduction in the passive region and increased the sensitivity to pitting corrosion.

Precipitates evolution and fracture mechanism of the isothermally solidified TLP bonding joints between 316LN stainless steel and IN718 Ni-based alloy

In this study, the dissimilar TLP bonding joints of Inconel 718 nickel-base alloy and AISI 316LN stainless steel free of brittle athermal solidification zone (ASZ) were obtained. It was recognized that a good metallurgical bonding is achieved at the interface between the isothermal solidification zone (ISZ) and diffusion affected zone on the side of IN718 alloy (hereafter referred to as DAZ-IN718), while the interface of ISZ and DAZ-316LN is more sensitive to crack initiation. A lot of precipitates were found in DAZ on both sides near the base metal, which were identified as Cr2B, Cr5B3, Nb3B2, and BN. Moreover, two different sizes of voids form at the ISZ/DAZ-316LN interface. The bigger voids are caused by BN phases, while the smaller voids were identified as Kirkendall voids. The tensile test results indicate that the tensile strength and elongation decrease with increasing bonding time. In-situ tensile tests and digital image correlation (DIC) analysis indicate that there are two factors that cause the fracture of dissimilar TLP bonding joints at the ISZ/DAZ-316LN interface. The first factor is the brittle BN phases and Kirkendall voids at the ISZ/DAZ-316LN interface. During tensile tests, dislocations slide along the slip surface until they are blocked by precipitates in the DAZ, resulting in extremely high-stress concentrations at these locations. Moreover, the second factor is the poor ability of DAZ-316LN to resist plastic deformation. The high degree of strain concentration in DAZ-316LN also promotes the formation of microcracks at the ISZ/DAZ-316LN interface.

Effect of Holding Time on Microstructure and Mechanical Properties of Dissimilar γ'‐Strengthened Superalloys TLP Joint

To achieve efficient connectivity of dissimilar γ'‐strengthened superalloy, transient liquid‐phase (TLP) diffusion bonding of 718Plus and Ni3Al‐based superalloys is carried out using BNi‐2 interlayer at a constant temperature of 1100 °C with holding times of 3, 15, 30, and 60 min. It is shown in the results that when the holding time is insufficient, isothermal solidification transforms into athermal solidification. Due to the enrichment of B and Cr elements in liquid phase, ternary eutectic consisting of γ, Ni3B, and CrB is formed at the joint center. Ternary eutectic with higher hardness (≈600 Hv) is poorly bonded to the matrix, which can easily become crack initiation location and significantly deteriorated the tensile properties. In addition, microhardness of the joint becomes more uniform and tensile strength gradually increases due to the reduction of eutectic with holding time increasing. Isothermal solidification completes and a joint without eutectic structure is formed at 1100 °C for 60 min. Diffusion of Al atoms leads to the formation of γ' with gradient size and tensile strength is comparable to that of base metal which is about 690.93 MPa.

Diffusion brazing of GH536 polycrystalline superalloy with IC10 single crystal superalloy using BNi-2 interlayer

Joining single crystal superalloy with polycrystalline superalloy has important applications in the aerospace industry. Here, the IC10 single crystal superalloy to GH536 polycrystalline superalloy was diffusion brazed using a BNi-2 filler alloy. The effects of bonding temperature and time on the microstructure evolution and mechanical properties of the GH536/IC10 joints were investigated in detail. The results elucidated that the joint brazed at a lower temperature and time (i.e., 1050 °C/30min) was composed of diffusion affected zone (DAZ), athermal solidification zone (ASZ), and isothermal solidification zone (ISZ). The secondary precipitates formed in DAZ were Cr-rich borides, Cr–Mo borides, and Cr–Mo–W borides. The ASZ was made up of Cr-rich borides, Ni-rich borides, Ni–Cr borides, and Ni-based solid solutions. These borides with high hardness were the potential source of cracks and caused the joints to fracture under a lower load. Raising bonding temperature and time gradually eliminated Ni-rich borides in ASZ and Cr-rich borides in DAZ, and improved the shear strength.

Microstructure Evolution of Athermal Solidification Zone and Its Effect on Mechanical Properties in Dissimilar Transient Liquid Phase Bonded Joint of IN718 Ni-Based Alloy/316LN Steel

Microstructure Evolution of Athermal Solidification Zone and Its Effect on Mechanical Properties in Dissimilar Transient Liquid Phase Bonded Joint of IN718 Ni-Based Alloy/316LN Steel

Transient liquid phase (TLP) bonding of Ti–6Al–4V/AISI 304 stainless steel using Cu/CNT composite interlayer

This paper investigates the idea of using Cu/CNT composite interlayer in the transient liquid phase (TLP) bonding of Ti–6Al–4V/AISI 304 stainless steel. In this investigation, initially TLP was carried out using a pure copper interlayer at 900, 950 and 1000 °C with the holding time 60 min. The TLP joining was then carried out at 900 °C with Cu/CNT interlayer, with the CNT weight percent, ranging from 0 to 3%. CNT was deposited on Cu foils, using electrophoretic deposition technique. Microstructure and mechanical properties of the joints were investigated with optical/electron microscopes, microhardness, and shear tests. Results showed that the interface microstructure can be divided into athermal solidification zone, isothermal solidification zone, and diffusion affected zone. The phase structure and compositions in CNT-containing samples are relatively similar to TLP samples with pure Cu interlayer. Results showed that CNT addition has expanded the diffusion areas and facilitated the diffusion across the interface. CNT addition up to 3 wt. % resulted in a significant increase in hardness up 500 VHN. The increase in hardness in the joint area can be related to the presence of various intermetallic compounds at the TLP region. The correlations between mechanical properties and microstructure and the implications of CNTs for mechanical properties of the joints are discussed.

Microstructural characteristics and mechanical properties of IC10 superalloy and (CoCrNi)94Al3Ti3 MEA joint brazed using NiCrSiB filler

This study focuses on the brazing of IC10 Ni 3 Al-based superalloy to (CoCrNi) 94 Al 3 Ti 3 medium-entropy alloy (MEA) using a NiCrSiB filler metal. The microstructure of the brazed joint was comprehensively investigated, and the forming mechanism of the joint was elucidated. The mechanical properties and fracture behavior of the joint were evaluated. The diffusion of boron from the filler to substrates led to the diffusion-affected zone (DAZ), and the M 3 B 2 - and M 5 B 3 -type boride were precipitated with the coherence of (3 1 0) BCT //(2 0 0) FCC (M 3 B 2 ) and (0 0 2) BCT //(2 0 0) FCC (M 5 B 3 ) adjacent to the IC10 and MEA substrate, namely the DAZ I and II respectively. In addition, the edge dislocation reduced the mismatch between the M 3 B 2 boride and the γ matrix. The isothermal solidification zone (ISZ) was formed near the DAZ when the liquidus temperature reached the brazing temperature due to the diffusion of boron and Si and the dissolution of substrates. The formation of ISZ was effectively activated at high brazing temperatures (1090, 1120, and 1150 °C). The athermal solidification zone (ASZ) was detected in the joint brazed at adopted temperatures, which mainly dominated by eutectic reactions and driven by cooling. The ASZ decreased shear strength of the defect-free joint, and readily accelerated initiation and propagation of cracks. The maximum shear strength of 554 MPa was obtained when the joint was brazed at 1120 °C for 10 min. The fracture mainly occurred in the ASZ (semi-cleavage), and passing through the DAZ (semi-cleavage) and ISZ (dimples). • The brazing of IC10 and (CoCrNi) 94 Al 3 Ti 3 MEA was achieved using a NiCrSiB filler. • The M 3 B 2 - and M 5 B 3 -type borides in the DAZ exhibited coherent with the matrix. • The microstructural evolution and mechanical properties were evaluated. • .

Microstructure and mechanical properties of TLP-bonded 9CrMoCoB heat-resistant steel with Ni–Cr–B interlayer

9CrMoCoB heat-resistant steel was transient liquid phase (TLP) bonded by using a Ni–Cr–B amorphous filler metal. Results indicated that the TLP-bonded joint was composed of three feature regions, and the precipitates in the diffusion affected zone (DAZ) were M23(C,B)6-type carboborides and M3B2-type borides with different morphologies and locations. Fine granular Fe2Mo-type Laves phases and MX-type carbides that existed in the original base metal were found in the grain. The carboborides and borides in the DAZ that grew with the increase in bonding time and temperature were reduced or completely dissolved after post weld heat treatment (PWHT). The joints without PWHT showed high strength and low elongation due to the high hardness and high hardenability of the matrix. The initiation of cracks occurred on borides in the athermal solidification zone and carboborides in the Ni-DAZ and passed through in the bonded seam, resulting in the reduction in the tensile strength of the bonded joints. The hardness of the joints was obviously reduced, and their toughness was obviously improved after PWHT. The highest tensile strength reached to 744 MPa when the TLP joints were bonded at 1150 °C for 30 min, which was comparable with the original base metal.

Relationship of isothermal solidification completion and precipitate formation with mechanical properties of Inconel 939 joints vacuum TLP bonded by an amorphous Ni–Cr–Fe–Si–B filler alloy

In this research, vacuum transient liquid phase bonding of Inconel 939 superalloy was performed using an amorphous Ni–Cr–Fe–Si–B filler alloy at different temperatures from 1060 °C to 1180 °C, and the microstructure and mechanical properties of the joints were investigated. The results showed that the bonding region can be categorized into three athermal solidification, isothermal solidification, and diffusion affected zones. The ASZ region consisted of a eutectic phase while the ISZ region included a Ni-rich gamma single-phase solid solution. Also, the DAZ involved cubic-shaped, needle-like and grain boundary-shaped borides. The width of DAZ increased with increasing the bonding temperatures, and it also led to a decrease in the ASZ/joint ratio. The ASZ was disappeared at 1180 °C. The highest hardness value was obtained for the DAZ region of the sample bonded at 1180 ᵒC, and a direct relationship was detected between the bonding temperature and ISZ hardness. The addition of bonding temperature also led to the improvement of the shear strength and joint efficiency. It was also found that an inverse relationship can be detected between the shear strength and the ASZ/joint ratio. A joint efficiency of ∼79% was obtained for the bonding temperature of 1180 °C.

Ductile Braze Repairs for Ni-Based Superalloys Using Novel MPEA Filler Metal

The performance of a newly developed multiprincipal-element alloy (MPEA) filler metal for brazing of nickel-based superalloys was directly compared to a conventional boron- and silicon-suppressed filler (BSSF) metal. The comparison was demonstrated on an Alloy 600 substrate with a brazing temperature of 1200°C. Single-phase solidification behavior and the absence of boron and silicon in the MPEA led to a joint microstructure devoid of eutectic constituents or brittle phases in brazes employing this filler metal. In the brazes using the conventional BSSF metal, incomplete isothermal solidification and subsequent athermal solidification of the residual liquid resulted in large particles of a chromium-rich boride phase distributed throughout the microstructure. Tensile testing of brazed butt joints at both room temperature and 600°C testing conditions demonstrated that the MPEA joints exhibited total ductility values at least one order of magnitude greater than that of BSSF joints, but they showed comparable yield strengths in both testing conditions. Fractographic assessment confirmed that boride phases nucleated cracks and resulted in brittle failure in the BSSF joints, while the MPEA joints exhibited extensive ductile microvoid coalescence. Fine-scale porosity and oxide inclusions may be the dominant factors limiting the overall ductility observed in the MPEA brazes.

Microstructure Evolution of Athermal Solidification Zone and its Effect on Mechanical Properties in Dissimilar Tlp Bonded Joint of In718 Ni-Based Alloy/ 316ln Steel

Microstructure Evolution of Athermal Solidification Zone and its Effect on Mechanical Properties in Dissimilar Tlp Bonded Joint of In718 Ni-Based Alloy/ 316ln Steel

Microstructure and mechanical properties of transient liquid phase bonding DD5 single-crystal superalloy to CrCoNi-based medium-entropy alloy

• The transient liquid phase bonding of DD5 single-crystal superalloy to CrCoNi-based medium-entropy alloy was achieved using a BNi-2 filler interlayer. • The M5B3-type boride (BCT) precipitated in the diffusion-affected zone exhibiting a coherent relationship of [ 2 4 0]BCT // [0 1 1]FCC and (0 0 2)BCT // (2 0 0)FCC with the FCC matrix. • The effect of the reaction phase properties on the joint performance was investigated. • The maximum shear strength of 752 MPa was obtained with the eutectic-free joint. This study focuses on the transient liquid phase (TLP) bonding of DD5 single-crystal superalloy to CrCoNi-based medium-entropy alloy (MEA) using a BNi-2 filler alloy. The microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated, and the microstructural evolution mechanism was investigated. The formation of the isothermal solidification zone (ISZ) depended on the diffusion of the melting-point depressants (Si and B elements) from the liquid filler into the DD5 and MEA substrates, as well as the dissolution of the substrates. Boron diffused along the γ channel of DD5 and reacted to form M 5 B 3 boride, herein referred to as the diffusion-affected zone (DAZ I). Similarly, the Cr 5 B 3 boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate (i.e., DAZ II). Additionally, a coherent orientation of [0] BCT // [0 1 1] FCC and (0 0 2) BCT // (2 0 0) FCC was detected between M 5 B 3 boride with a body-centered tetragonal (BCT) structure and the face-centered cubic (FCC) matrix. The performance of the joint was dominated by the properties of the bonding seam. As the bonding time increased from 20 to 80 min, the athermal solidification zone (including eutectic microstructure) was gradually replaced by the ISZ exhibiting excellent plastic deformation capability, and the shear strength of the joint was improved. The maximum shear strength (752 MPa) was achieved when the eutectic-free joint was bonded at 1050 °C for 80 min. The fracture morphology revealed a mixture mode, indicating the initiation of cracks in the DAZ II, mainly propagating in the ISZ, and passing through the DAZ I.

Microstructural and mechanical properties assessment of transient liquid phase bonding of CoCuFeMnNi high entropy alloy

The transient liquid phase (TLP) bonding of CoCuFeMnNi high entropy alloy (HEA) was studied. The TLP bonding was performed using AWS BNi-2 interlayer at 1050 °C with the TLP bonding time of 20, 60, 180 and 240 min. The effect of bonding time on the joint microstructure was characterized by SEM and EDS. Microstructural results confirmed that complete isothermal solidification occurred approximately at 240 min of bonding time. For samples bonded at 20, 60 and 180 min, athermal solidification zone was formed in the bonding area which included Cr-rich boride and Mn3Si intermetallic compound. For all samples, the γ solid solution was formed in the isothermal solidification zone of the bonding zone. To evaluate the effect of TLP bonding time on mechanical properties of joints, the shear strength and micro-hardness of joints were measured. The results indicated a decrement of micro-hardness in the bonding zone and an increment of micro-hardness in the adjacent zone of joints. The minimum and maximum values of shear strength were 100 and 180 MPa for joints with the bonding time of 20 and 240 min, respectively.

Effect of microstructure aspects on mechanical properties of nanoparticle-assisted transient liquid phase (NP-TLP) joints for AZ31 alloy

To study the effect of nanoparticles on strengthening the transient liquid phase (TLP) joints of AZ31 alloy, different interlayers including pure copper, pure copper+TiO 2 nanoparticles, pure copper+Al 2 O 3 nanoparticles and pure copper+SiC nanoparticles were used. The pure copper was coated on the surfaces to be joined via electroplating. The samples were TLP bonded at 525 °C for 1 and 2 h under the pressure of 1 MPa, in an atmosphere-controlled furnace. After that, the microstructure of the joints were studied using optical and scanning electron microscopy and phase analysis as conducted using Energy-dispersive X-ray spectroscopy. The joints' shear strength was evaluated via a tensile test machine equipped with a special designed fixture and X-Ray Diffraction was utilized to analyze the related fracture surfaces. Microstructural studies showed that athermal solidification induced eutectic compounds at the joints were reduced with increasing bonding time and therefore, the isothermal solidification became more completed. This also increased the homogenity and uniformity of the microstructure and the joint's shear strength. The highest and lowest shear strength was observed for the joints made using pure copper+TiO 2 nanoparticles and pure copper+SiC nanoparticles-containing interlayers, respectively, about 90% and 15% of the base metal's shear strength. Also, the shear strength of the joints made using pure copper+Al 2 O 3 nanoparticles was higher for the 20 nm particles, compared to the 50 nm ones. • Exploring TLP bonding process for AZ31 alloy as an Mg-based one • Using nanoparticles-including interlayers with different materials and sizes • A reverse relationship between the nanoparticle size and joint's shear strength • Obtaining the highest joint's shear strength about 98% of that of the base metal • ASZ size and nanoparticles surface area as the factors of the joint's strength

Investigation on the microstructure and mechanical properties of CoCrFeNi high-entropy alloy joint bonded with BNi2 interlayer

• The athermal solidification zone and isothermal solidification zone of CoCrFeNi joint are determined to be γ phase and high entropy Ni-rich FCC phase, respectively. No eutectic products containing borides precipitated in the athermal solidification zone. • With increasing the bonding temperature or prolonging the holding time, the growths of ISZ and DAZ present a synchronous trend. The precipitating location of CrxBy is changed from grain interior to grain boundaries. • The maximum bonding strength of CoCrFeNi joint is ∼ 429 MPa, which is about 75 % of base metal strength. • The impact of Cr depletion on the performance of CoCrFeNi joint is less severe than that on conventional alloys joints. The strategy of bonding high-entropy alloys (HEAs) is of vital significance for producing complex engineering components available to extreme conditions. In this work, transient liquid phase (TLP) bonding was applied to join CoCrFeNi HEAs using an amorphous Ni-Cr-Si-B interlayer (BNi2). The interfacial microstructure evolution, mechanical properties and bonding mechanism of the joints were evaluated. Results indicated three reaction products in the different zones of joints, including the γ phase in the athermal solidification zone (ASZ), high-entropy Ni-rich face-centered cubic (FCC) phase in the isothermal solidification zone (ISZ) and a high density of CrxBy precipitates with different morphologies (blocky, punctate and acicular) in the diffusion affected zone (DAZ 7 ). With increasing the bonding temperature or holding time, the width of ISZ and DAZ almost presented a synchronous growing trend, and the location of CrxBy precipitates was changed from grain interior to grain boundaries. Tension shear test showed excellent bonding strength of all the bonded joints due to the formation of the ASZ free of eutectic products containing borides, and the maximum bonding strength could reach 429 MPa, which is about 75 % of the base metal (BM) strength. The joint ruptured at the CoCrFeNi BM adjacent to the lapping area in ductile fracture mode. This work is expected to facilitate the fabrication and repair of complex CoCrFeNi-related components in future.