Two-step heating transient liquid phase bonding of Inconel 738LC

Amirkhani, Alireza; Beidokhti, Behrooz; Shirvani, Kourosh; Rahimipour, Mohammad Reza

doi:10.1016/j.jmatprotec.2018.10.008

Cited by 13 publications

(7 citation statements)

References 21 publications

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“…As a result the width of ISZ widened as the diffusion of the MPD element grows. This observation is in line with other studies [15,28,29]. The DAZ which composed of second-phase precipitates distributed in the BM was formed as a result of solid-state diffusion and segregation of interlayer elements into the BM.…”

Section: Effect Of Bonding Time On Joint Microstructuresupporting

confidence: 93%

“…In another study 45MnMoB steel was joint by temperature gradient TLP process which resulted in a homogenous joint with a cellular interface and acceptable mechanical strength [14]. Joining of Inconel 738 was also studied with this method and the results showed that shorter bonding time can be applied in comparison to conventional method [15].…”

Section: Introductionmentioning

confidence: 99%

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Transient Liquid Phase Bonding of 17-4-PH Stainless Steel Using Conventional and Two-Step Heating Process

2020

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Conventional and two-step heating transient liquid phase bonding (TLP) experiments of martensitic precipitation hardening stainless steel 17-4-PH were studied employing AMS 4777 braze filler at temperature of 1050 °C for different times (15 to 90 min) to accomplish the ideal brazing condition. The effect of TLP methods and bonding conditions on the microstructure and shear bond strength was investigated. The critical bonding time for isothermal solidification in conventional and two-step heating TLP was 60 min and 45 min, respectively. The microstructure of isothermal solidification zone consisted of Ni-rich solid solution phase. Eutectic constituents Cr-rich boride and Ni 3 Si were formed in the joint centerline in the athermally solidified zone. In the conventional method planar interface was formed, however in TLP bonding under temperature gradient non-planar interface was formed, high angel grain boundaries merged at the end of isothermal solidification and homogenous bond was produced. Due to the decrease of athermally solidified zone the shear strength increased by increasing the holding time and when using the two-step heating process because of better metal to metal contact, the shear strength was higher. The optimum condition was a temperature gradient TLP in 60 min bonding time, which led to shear strength of 435 MPa.

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Section: Effect Of Bonding Time On Joint Microstructuresupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Transient Liquid Phase Bonding of 17-4-PH Stainless Steel Using Conventional and Two-Step Heating Process

2020

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“…This could be related to the formation of Cr-rich and Mo-rich boride particles in DAZ. 26 It should be noted that the high hardness of DAZ also remained after the completion of the isothermal solidification (Figure 6(b)). The lowest hardness was found in ISZ.…”

Section: Resultsmentioning

confidence: 88%

“…The mechanisms of formation of all three zones and their microstructural features as well as elemental and phase constituents of the zones have been discussed in detail elsewhere. 26 According to Figure 2(b), Ni-rich/Cr-rich borides were formed in the matrix, if the isothermal solidification stage could not be completed. As shown in Table 2, precipitates of ASZ could be Ni 3 Si, Ni 3 B, and CrB.…”

Section: Resultsmentioning

confidence: 99%

Effect of two-step heating transient liquid phase bonding on microstructure and mechanical behaviour of IN-738LC gas turbine components

Amirkhani

Shirvani

Beidokhti

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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The long isothermal solidification and homogenization time is the major concern in repairing turbine parts by the conventional transient liquid phase method. In this study, microstructure and morphology of the proposed two-step heating transient liquid phase joints were compared to results of the conventional ones conducted at the same temperature. After the isothermal solidification, deleterious precipitates such as Ni3Si, Ni3B and CrB were removed. The application of the two-step technique increased the shear strength of the joints up to 28% (516–674 MPa) due to collision of two non-planar interfaces and formation of the longer bonding line. The shear fracture surfaces of all bonds with the complete isothermal solidification stage represent a dimple pattern that is characterized by ductile fracture. The stress-rupture life of the joint at 982 °C was about 85% of the superalloy service life at this temperature.

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“…When the time at the brazing temperature is not sufficient for isothermal solidification of the entire joint, and the onset of cooling follows, brittle intermetallic phases can form via eutectic transformation of the remaining melt, enriched in these elements due to their low solubility in the advancing gamma matrix phase, usually occurring along the joint center. [7,8] A joint examined at this stage may exhibit two phenomena often referred to as the isothermally solidified zone (ISZ), and the athermally solidified zone (ASZ). Furthermore, fast diffusing elements such as boron can react with the base metal elements, creating what is commonly referred to as a diffusion-affected zone (DAZ) at the interface of filler metal and into the base metal, [9,10] which may remain even if isothermal solidification is complete within the joint.…”

Section: Introductionmentioning

confidence: 99%

Development of a Novel Ni-Based Multi-principal Element Alloy Filler Metal, Using an Alternative Melting Point Depressant

Hardwick

Rodgers

Pickering

et al. 2021

Metall Mater Trans A

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Brazing is a crucial joining technology in industries where nickel-superalloy components must be joined. Nickel-based brazing filler metals are extensively employed, possessing excellent mechanical properties, corrosion resistance, and retained strength at elevated temperatures. To function as a filler metal, the alloy melting point must be reduced to below that of the materials being joined, but the addition of melting point depressants (MPDs) such as boron, silicon, and phosphorus can, however, lead to the formation of brittle intermetallics, potentially compromising the joint performance. In the present work, a novel multi-principal element brazing alloy (in the style of a high entropy alloy), utilizing Ge as an alternative MPD along with a reduced B addition, is investigated. The design process considered binary phase diagrams and predictions based on Thermo-Calc software and empirical thermodynamic parameters. The alloy was used to vacuum braze nickel-superalloy Inconel-718, and microstructural and mechanical investigations are reported. The maximum shear strength achieved was 297 MPa with a brazing temperature of 1100 °C and 60-minute hold time, with isothermal solidification completed. Shear strength was only slightly reduced with increased joint width. Assessments are made of the ability to accurately predict properties of multi-principle element alloys using Thermo-Calc software and empirical thermodynamic parameters.

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Two-step heating transient liquid phase bonding of Inconel 738LC

Cited by 13 publications

References 21 publications

Transient Liquid Phase Bonding of 17-4-PH Stainless Steel Using Conventional and Two-Step Heating Process

Transient Liquid Phase Bonding of 17-4-PH Stainless Steel Using Conventional and Two-Step Heating Process

Effect of two-step heating transient liquid phase bonding on microstructure and mechanical behaviour of IN-738LC gas turbine components

Development of a Novel Ni-Based Multi-principal Element Alloy Filler Metal, Using an Alternative Melting Point Depressant

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