Powder Metallurgy Repair of Turbine Components

Ellison, K. A.; Lowden, P.; Liburdi, J.

doi:10.1115/1.2906799

Cited by 24 publications

(16 citation statements)

References 7 publications

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“…The Liburdi Powder Metallurgy (LPM") process [13] was designed as a hybrid, wide gap process that allows the defects to be mechanically removed in a manner similar to welding ( Figure 12) and then repaired using a powder metallurgy putty of matching or custom composition, to achieve the desired mechanical and metallurgical properties [14][15] [16]. The resultant metallurgical bond, shown in Figure 13 exhibits excellent fusion to the base metal, as well as no evidence of prior powder particles and microstructure.…”

Section: Advanced Brazingmentioning

confidence: 99%

Enabling Technologies for Advanced Turbine Component Life Extension

Liburdi¹,

Lowden²

1999

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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The evolution in materials and turbine design has resulted in the parallel development of advanced equipment and processes capable of manufacturing and repairing critical engine components. Modern, vision based automated welding systems are now widely utilized for precise, low heat welding of crack sensitive alloys. Unique powder metallurgy processes such as LPM™ allow repairs to be engineered for higher localized strength or better wear properties for applications such as abrasive tips. Significant changes have also occurred in the stripping and coating processes with the introduction of sophisticated vapour-based technologies. These advanced technologies are extending opportunities for repair and life extension of turbine components, but the availability and costs associated with these enabling technologies, along with the difficulty in obtaining approvals, may restrict sources for advanced component repairs.

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Section: Advanced Brazingmentioning

confidence: 99%

Enabling Technologies for Advanced Turbine Component Life Extension

Liburdi¹,

Lowden²

1999

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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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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“…service (Anthony and Goward, 1988). Such methods have been developed and applied not only by the OEM's but also by independent repair facilities (Duvall, et al, 1978;Smith, Jr. et al, 1984;Ellison, Lowden and Liburdi, 1992) In spite of these earlier successes, there is a continuing need in the industry to improve the material properties and extend the repair limits beyond current DB and WGB processes. Although some reports indicate that WGB processes are capable of achieving tensile and creep properties approaching those of the parent superalloys, independent testing and field experience suggests that these repair materials do not always possess the same degree of oxidation and hot corrosion resistance as the parent alloys (Jahnke and Demny, 1983;Boone, Ellison and Liburdi, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…Liburdi Engineering Ltd. has recently developed and introduced the LPM'"' repair process which is designed to extend the repair limits of existing WGB as well as TIG welding processes (Ellison, Lowden, and Liburdi, 1992). Based on its composition, the LPM T"' repair material was also expected to offer improved hot corrosion resistance compared to the existing WGB materials.…”

Section: Introductionmentioning

confidence: 99%

Repair Joints in Nickel-Based Superalloys With Improved Hot Corrosion Resistance

Ellison¹,

Lowden²,

Liburdi³

et al. 1993

Volume 3B: General

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Sample repair joints in the nickel-base superalloys Inconel IN-713 and IN-738 were tested in the laboratory for Type I high temperature hot corrosion (HTHC) resistance at 900°C. The joints were produced using a conventional “wide-gap” brazing process, having a composition similar to IN-718, and a novel powder metallurgy repair technique LPM™ which in this study had a composition similar to alloy IN-738. Metallographic analysis of the resulting structures showed that the IN-718 based repairs, with and without simple aluminide coatings, had suffered extensive intergranular attack of the braze joints. However, the HTHC resistance of cast IN-718 was found to be excellent under identical test conditions. A comparison of the uncoated LPM™ repair joints and cast IN-738 revealed only subtle differences in the morphology of the corrosion products; the maximum depths of attack were similar in each case. Silicon modified aluminide coatings provided a slight reduction in the rate of attack for the IN-738 alloy, while simple aluminide coatings were less resistant to HTHC than the base alloy. Similar results were found for the LPM™ joints, however localized coating penetration was observed in the vicinity of boride particles embedded in the coatings. These differences in behaviour were interpreted with reference to the chemical and structural changes brought about by the use of varying levels of boron as a melting point depressant in the repair layers.

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Powder Metallurgy Repair of Turbine Components

Cited by 24 publications

References 7 publications

Enabling Technologies for Advanced Turbine Component Life Extension

Enabling Technologies for Advanced Turbine Component Life Extension

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

Repair Joints in Nickel-Based Superalloys With Improved Hot Corrosion Resistance

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