Effect of Ruthenium, Rhenium and Yttria Additions on the Microstructure of Wide Gap Brazing of IN738

2007 ◽  
Author(s):  
Xiao Huang ◽  
Scott Yandt ◽  
Doug Nagy ◽  
Matthew Yao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Life Cycle Cost ◽  
Filler Metal ◽  
Braze Alloy ◽  
Cost Effective ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Wide Gap ◽  
Boride Phases

Modern gas and steam turbine components are subject to severe thermomechanical loads and extremely high temperature in order to provide increased performance and efficiency. Most high temperature turbine components are made of superalloys specifically developed for high temperature and high mechanical stress applications but at considerable cost. Defects may occur during manufacturing of superalloy castings as well as after service. Repair of these components, rather than replacement, helps to reduce the life cycle cost. Wide gap brazing is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. With proper control of the braze alloy and brazing cycle, the repaired region has been reported to posses mechanical properties approaching that of the parent materials. In order to further improve the mechanical properties of the repaired region and to explore the possibility of employing the wide gap brazing method to repair single crystal components in the future, three alloying additions, Ruthenium (Ru), Rhenium (Re) and yttria (Y2O3), were incorporated into the braze filler metal by mechanical alloying. The microstructures of the wide gap brazed joints with Ru, Re and yttria additions were studied and compared to a braze joint with standard wide gap braze alloys of IN738 and AWS BNi-9. It has been found that two types of borides formed in all braze alloys, namely eutectic γ-Ni-rich and boride phases and discrete boride containing primarily Cr and W (or Ru). The addition of Ru to the filler metal did not seem to modify the microstructural constituents after brazing. However, Ru partitioned strongly to the discrete borides. No isolated elemental Ru region was observed. On the other hand, Re addition was found to change the occurrence and distribution of both types of borides. The eutectic boride constituent was significantly reduced and finer discrete boride particles were observed. The addition of yttria did not change the boride formation but led to the generation of more voids in the brazed joint.

Effect of Tungsten Addition on the Nucleation of Borides in Wide Gap Brazed Joint

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Daniel McGuire ◽  
Xiao Huang ◽  
Doug Nagy ◽  
Weijie Chen
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Thermal Fatigue ◽  
Braze Alloy ◽  
Microstructural Analysis ◽  
Cost Effective ◽  
Filler Alloy ◽  
Thermal Fatigue Life ◽  
Brazed Joint ◽  
Wide Gap

Wide gap brazing (WGB) is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. However, it has been shown that WGB joints of nickel-based superalloys suffer from reduced ductility and thermal fatigue life due to the presence of brittle intermetallics and porosities in the brazed joint. In order to disperse the brittle intermetallic compounds, potentially increase the ductility of the repaired region, and reduce the risk of the thermomechanical fatigue failure, elemental tungsten (W) was added to the braze additive filler alloy IN738 by mechanical alloying. The alloyed IN738 was then brazed with the addition of 30 wt %, 50 wt %, and 80 wt % of braze alloy (BNi-9). After brazing at 1200°C for 20 min, microstructural analysis of WGB joints showed a decreasing trend of discrete boride size and the amount of eutectic and script-shaped borides with the increases of W. The increase in the braze alloy to additive filler alloy ratio diminished the effect of W addition due the dissolution of W particulates.

Powder Metallurgy Repair of Turbine Components

1994 ◽  
Vol 116 (1) ◽  
pp. 237-242 ◽  
Author(s):  
K. A. Ellison ◽  
P. Lowden ◽  
J. Liburdi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Filler Metal ◽  
Repair Process ◽  
Parent Material ◽  
High Temperature Alloys ◽  
Wide Gap ◽  
Mechanical Cleaning ◽  
Repair Techniques

An advanced powder metallurgy repair process called Liburdi Powder Metallurgy (LPM) has been developed for the repair, overlay or joining of nickel and cobalt-based high-temperature alloys. This process involves mechanical cleaning, followed by the application and consolidation of a filler metal powder, which has substantially the same composition as the base metal, and produces joints with mechanical properties similar to those of the parent material. While previously activated braze or “wide-gap” repair processes have been limited to clearances of approximately 1 mm, the LPM technique has the ability to bridge larger gaps of over 5 mm. In addition, the LPM joints contain significantly lower concentrations of melting point depressants such as silicon and boron than conventional wide-gap repair techniques and exhibit superior microstructural features. The characteristics and typical applications of the LPM process for blade and vane repairs are highlighted and the results of laboratory and engine tests are discussed.

Brazing Process to Repair Wide Gap Cracks of Inconel 738 Superalloy Components

2009 ◽  
Vol 1242 ◽  
Author(s):  
Isidro Guzmán ◽  
Alejandro Garza ◽  
Felipe García ◽  
Jesús Castillo
Keyword(s):  
Cost Effective ◽  
Isothermal Solidification ◽  
Nickel Base Superalloy ◽  
Cost Effective Technique ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Wide Gap ◽  
Nickel Base ◽  
Eds Microanalysis ◽  
Base Superalloy

ABSTRACTBrazing process is a cost effective technique to repair wide gap cracks in turbine components made from difficult to weld nickel base superalloys. In this process boron and silicon are used as melting point depressants, however, form hard and brittle intermetallic compounds with nickel (eutectic phases) which are detrimental to the mechanical properties of brazed joints. In this paper the effect of brazing parameters such as temperature and time on final microstructure of brazed joint of nickel base superalloy Inconel 738 using a commercial filler metal alloy (Ni-11Cr-3.5Si-2.25B-3.5Fe) was investigated. The microstructure of the joint layer was characterized by optical and scanning electron microscopy; chemical composition was carried out by energy dispersive X-ray spectrometry (EDS) microanalysis and microhardness testing. The results showed that the formation of eutectic microconstituents, within the joint regions, was significantly influenced by the brazing parameters and gap size, also that formation of eutectic constituents decreased by allowing a sufficient amount of time for a complete isothermal solidification to take place at the brazing temperature.

Effect of Tungsten Addition on the Nucleation of Borides in Wide Gap Brazed Joint

2009 ◽  
Author(s):  
Daniel McGuire ◽  
Xiao Huang ◽  
Doug Nagy ◽  
Weijie Chen
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Braze Alloy ◽  
Microstructural Analysis ◽  
Cost Effective ◽  
Filler Alloy ◽  
Mechanical Fatigue ◽  
Thermal Fatigue Life ◽  
Brazed Joint ◽  
Wide Gap

Wide gap brazing (WGB) is a cost effective and reliable means to repair gas turbine hot section components with defect sizes exceeding 0.3 mm. However, it has been shown that WGB joints of nickel-based superalloys suffer from reduced ductility and thermal fatigue life due to the presence of brittle intermetallics and porosities in the brazed joint. In order to disperse the brittle intermetallic compounds, potentially increase the ductility of the repaired region, and reduce the risk of the thermo-mechanical fatigue failure, elemental tungsten (W) was added to the braze additive filler alloy IN738 by mechanical alloying. The alloyed IN738 was then brazed with the addition of 30, 50 and 80 wt% of braze alloy (BNi-9). After brazing at 1200°C for 20 minutes, microstructural analysis of WGB joints showed a decreasing trend of discrete boride size and the amount of eutectic and script-shaped borides with the increases of W. The increase in the braze alloy to additive filler alloy ratio diminished the effect of W addition due the dissolution of W particulates.

scholarly journals Comparison of Microstructure and Mechanical Properties of Induction and Vacuume Brazed Joint of Titanium Via Copper and Ag-Cu Eutectic Filler Metal / Mikrostruktura I Właściwości Mechaniczne Połączeń Tytanu Lutowanych Indukcyjnie I Próżniowo Z Użyciem Spoiwa Miedzianego I Eutektycznego Ag-Cu

2015 ◽  
Vol 60 (4) ◽  
pp. 2593-2598 ◽  
Author(s):  
M. Różański ◽  
D. Majewski ◽  
K. Krasnowski
Keyword(s):  
Mechanical Properties ◽  
Filler Metal ◽  
Chemical Properties ◽  
Metallographic Examination ◽  
Air Atmosphere ◽  
Microstructure And Mechanical Properties ◽  
Physico Chemical ◽  
Brazed Joints ◽  
Brazed Joint

This study presents the basic physico-chemical properties and describes the brazeability of titanium. The work contains the results of macro and microscopic metallographic examination as well as the results of strength-related tests of vacuum and induction brazed joints made of Grade 2 technical titanium using the Cu 0.99 and Ag 272 filler metal interlayers and F60T flux intended for titanium brazing in the air atmosphere.

scholarly journals Powder Metallurgy Repair of Turbine Components

1992 ◽  
Author(s):  
K. A. Ellison ◽  
P. Lowden ◽  
J. Liburdi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Filler Metal ◽  
Repair Process ◽  
Parent Material ◽  
High Temperature Alloys ◽  
Wide Gap ◽  
Mechanical Cleaning ◽  
Repair Techniques

An advanced powder metallurgy repair process called Liburdi Powder Metallurgy (LPM)1 has been developed for the repair, overlay or joining nickel and cobalt-based high temperature alloys. This process involves mechanical cleaning, followed by the application and consolidation of a filler metal powder which has substantially the same composition as the base metal, and produces joints with mechanical properties similar to those of the parent material. While previous activated braze or “wide-gap” repair processes have been limited to clearances of approximately 1 mm, the LPM technique has the ability to bridge larger gaps of over 5 mm. In addition, the LPM joints contain significantly lower concentrations of melting point depressants such as silicon and boron than conventional wide-gap repair techniques and exhibit superior microstructural features. The characteristics and typical applications of the LPM process for blade and vane repairs are highlighted and the results of laboratory and engine tests are discussed.

Microstructure and Mechanical Properties of the Wide-Gap Region Brazed with Various Powder Mixing Ratios of Additive to Filler Metal Powders

2006 ◽  
Vol 118 ◽  
pp. 479-484 ◽  
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun
Keyword(s):  
Mechanical Properties ◽  
Metal Powder ◽  
Room Temperature ◽  
Filler Metal ◽  
Metal Powders ◽  
Powder Mixing ◽  
Factors Affecting ◽  
Mixing Ratios ◽  
Microstructure And Mechanical Properties ◽  
Wide Gap

This study investigated the microstructure and mechanical properties of the wide-gap region brazed with various powder mixing ratios of additive powder (IN738) to filler metal powder (DF4B). The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr at 1230°C for 1 hr. The microstructure of the brazed region was analyzed by FESEM and AES. The wide-gap region brazed with 60wt.% IN738 additive powder and 40 wt.% DF 4B filler metal powder had a microstructure consisting of Ni solid solution + γ' and (Cr, W)2B. The fracture strength of the wide-gap region brazed with 60 wt.% IN738 additive and 40 wt.% DF 4B powder was as high as 832 MPa at room temperature. It was found that the (Cr, W)2B and pores in the brazed region are important microstructural factors affecting the mechanical properties of the wide-gap brazed region.

Mechanical Properties and Structure of Laser Beam and Wide Gap Brazed Joints Produced Using Mar M247-Amdry DF3 Powders

2018 ◽  
Author(s):  
Alexandre Gontcharov ◽  
Yuan Tian ◽  
Paul Lowden ◽  
Mathieu Brochu
Keyword(s):  
Mechanical Properties ◽  
Laser Beam ◽  
Dendritic Structure ◽  
Gamma Prime ◽  
High Gamma ◽  
Weld Properties ◽  
Bulk Chemical ◽  
Brazed Joints ◽  
Properties Of Materials ◽  
Wide Gap

The microstructure and mechanical properties of materials produced by Wide Gap Brazing (WGB) and Laser Beam (LBW) cladding with different blends of Mar M247 and Amdry DF-3 brazing powders were studied. It was shown that LBW Mar M247 based materials comprised of 0.6 to 1 wt. % B were weldable. The weld properties were superior to WGB deposits with the same bulk chemical composition, due to the formation of a dendritic structure typical for welded joints, and the precipitation of cuboidal borides of Cr, Mo, and W in the ductile Ni-Cr based matrix. Both materials were found to have useful properties for 3D additive manufacturing (AM) and repair components manufactured from high gamma prime precipitation hardened superalloys.

scholarly journals Evaluation of Biomedical Ti/ZrO2 Joint Brazed with Pure Au Filler: Microstructure and Mechanical Properties

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 526
Author(s):  
Yuzhen Lei ◽  
Hong Bian ◽  
Wei Fu ◽  
Xiaoguo Song ◽  
Jicai Feng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometry ◽  
Filler Metal ◽  
Interfacial Microstructure ◽  
Holding Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Medical Products ◽  
Metallurgical Bonding ◽  
Brazed Joints

Titanium and zirconia (ZrO2) ceramics are widely used in biomedical fields. This study aims to achieve reliable brazed joints of titanium/ZrO2 using biocompatible Au filler for implantable medical products. The effects of brazing temperature and holding time on the interfacial microstructures and mechanical properties of titanium/Au/ZrO2 joints were fully investigated by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). The results indicated that the typical interfacial microstructure of the titanium/Au/ZrO2 joint was titanium/Ti3Au layer/TiAu layer/TiAu2 layer/TiAu4 layer/TiO layer/ZrO2 ceramic. With an increasing brazing temperature or holding time, the thickness of the Ti3Au + TiAu + TiAu2 layer increased gradually. The growth of the TiO layer was observed, which promoted metallurgical bonding between the filler metal and ZrO2 ceramic. The optimal shear strength of ~35.0 MPa was obtained at 1150 °C for 10 min. SEM characterization revealed that cracks initiated and propagated along the interface of TiAu2 and TiAu4 reaction layers.

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