Joint Characterisation for Repair Brazing of Superalloys

Heikinheimo, Liisa; Laukkanen, Anssi; Veivo, Juha

doi:10.1007/bf03263404

Cited by 11 publications

(6 citation statements)

References 2 publications

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“…Therefore, the most common technology of filling cracks is the repair by high temperature diffusion brazing [3,4,6,7]. This repair technology is characterized by the use of a braze alloy, similar to the base material, which is enhanced by a fast diffusing melting point depressant like boron and/or silicon inducing solidification by diffusion into the base material [3,[7][8][9][10][11]. Due to the high stresses in turbine components, the primary purpose of healing is to produce a single crystalline microstructure within the brazed gap which means that an epitaxial solidification is achieved.…”

Section: Introductionmentioning

confidence: 99%

Fast Epitaxial High Temperature Brazing of Single Crystalline Nickel Based Superalloys

Laux

Piegert

Rösler

2009

Journal of Engineering for Gas Turbines and Power

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A new high temperature brazing technology for the repair of turbine components made of single crystalline nickel based superalloys has been developed. It allows the repair of single crystalline parts by producing an epitaxially grown braze gap within very short times. In contrast to commonly used brazing technologies, the process is not diffusion based but works with consolute systems, particularly nickel-manganese alloys. Brazing experiments with 300 m wide parallel braze gaps, as well as V-shaped gaps with a maximum width of 250 m, were conducted. Furthermore, thermodynamic simulations, with the help of THERMOCALC software, Version TCR, were carried out to identify compositions with a suitable melting behavior and phase formation. With the new alloys complete, epitaxial bridging of both gap shapes has been achieved within brazing times as short as 10 min.

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Section: Introductionmentioning

confidence: 99%

Fast Epitaxial High Temperature Brazing of Single Crystalline Nickel Based Superalloys

Laux

Piegert

Rösler

2009

Journal of Engineering for Gas Turbines and Power

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“…The average Vickers hardness observed from several indentations are summarized in Table 5-2. It can be seen that the hardness of both the eutectic and discrete carbide phases were significantly higher than the IN-738 substrate or the primary y-Ni, as was found in other studies [65], [66]. The hardness observed for the IN-738 substrate, the eutectics, and the primary y-Ni are consistent with the results of other studies, however the hardness of the discrete Cr,W-rich carbides was found to be higher than was found in previous studies for Cr-borides commonly observed in brazing of IN-738.…”

Section: Microhardness Measurementsupporting

confidence: 82%

Development and characterization of braze repair technology for gas turbine hot section components

Henhoeffer¹

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“…Thus, singlecrystalline components can be repaired, reproducing the single-crystalline microstructure in the braze gap. [5,[7][8][9][10][11] This is particularly attractive in view of the severe thermomechanical loading of these components.…”

Section: Introductionmentioning

confidence: 99%

Braze Alloy Development for Fast Epitaxial High-Temperature Brazing of Single-Crystalline Nickel-Based Superalloys

Laux

Piegert

Rösler

2008

Metall Mater Trans A

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For the repair of single-crystalline turbine components, fabricated from nickel-based superalloys, a new high-temperature brazing technology has been developed. Cracks in single-crystalline parts can be repaired by reproducing the single-crystalline microstructure over the complete gap width within very short brazing times. Nickel-manganese-based alloys were identified as systems that provide very high, epitaxial solidification rates. In contrast to commonly used braze alloys, such as nickel-boron or nickel-silicon systems, the process is not completely diffusion controlled but works with consolute systems. For brazing experiments 300-lm-wide parallel gaps as well as V-shaped gaps with a maximum width of 250 lm were used. A complete epitaxial solidification, that is, the absence of large-angle grain boundaries, could be achieved within brazing times, being up to 100 times shorter compared to commonly used transient-liquid-phase bonding technologies. To quantify the misorientation relative to the base material and the composition within and near the filled gaps, the results of the brazing experiments were visualized by means of light microscopy and scanning electron microscopy (SEM). Furthermore, electron backscatter diffraction (EBSD) analyses and energy dispersive X-ray (EDX) analyses were conducted.

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Joint Characterisation for Repair Brazing of Superalloys

Cited by 11 publications

References 2 publications

Fast Epitaxial High Temperature Brazing of Single Crystalline Nickel Based Superalloys

Fast Epitaxial High Temperature Brazing of Single Crystalline Nickel Based Superalloys

Development and characterization of braze repair technology for gas turbine hot section components

Braze Alloy Development for Fast Epitaxial High-Temperature Brazing of Single-Crystalline Nickel-Based Superalloys

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