Wide-Gap Brazing of IN738 and the Bonding Strength Using Ni-Based Filler Metal Powders

2007 ◽  
pp. 1449-1452
Author(s):  
Y.H. Kim ◽  
Il Ho Kim ◽  
K.T. Kim ◽  
Seung Y. Shin
Keyword(s):  
Bonding Strength ◽  
Filler Metal ◽  
Metal Powders ◽  
Wide Gap

Wide-Gap Brazing of IN738 and the Bonding Strength Using Ni-Based Filler Metal Powders

2007 ◽  
Vol 345-346 ◽  
pp. 1449-1452 ◽  
Author(s):  
Yong Hwan Kim ◽  
Il Ho Kim ◽  
K.T. Kim ◽  
Seung Y. Shin
Keyword(s):  
Tensile Strength ◽  
Metal Powder ◽  
Bonding Strength ◽  
Room Temperature ◽  
Filler Metal ◽  
Eutectic Structure ◽  
Metal Powders ◽  
Powder Mixing ◽  
Mixing Ratios ◽  
Wide Gap

The microstructure and bonding strength of the wide-gap region brazed with different filler metal powder (BNi-3 and DF 4B) and various powder mixing ratios of additive powder to filler metal powder were investigated. The microstructure characterization showed that Cr borides with a blocky morphology were existed in the brazed region in both filler metal powder. The bonding strength of the wide-gap region brazed with 60 wt.% IN738 additive and 40 wt.% DF 4B powder exhibited 92% tensile strength of IN738 superalloy at room temperature. The Cracks in the wide-gap brazed region initiated at the intermetallic compound and eutectic structure, and then propagated through them.

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.

Phase Analysis in the Region Brazed with Ni-14Cr-10Co-3.5Al-2.5Ta-2.8B Filler Metal Using Electron Backscatter Diffraction

2008 ◽  
Vol 569 ◽  
pp. 93-96 ◽  
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun
Keyword(s):  
Solid Solution ◽  
Filler Metal ◽  
Electron Backscatter Diffraction ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Metal Powders ◽  
Orthorhombic Structure ◽  
Electron Backscatter ◽  
Wide Gap ◽  
Backscatter Diffraction

The phases formed in the wide-gap region brazed with Ni-14Cr-10Co-3.5Al-2.5Ta-2.8B filler metal powder in IN738 superalloy were investigated by electron backscatter diffraction (EBSD). The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr at 1503 K. The region brazed with filler metal powders had a microstructure consisting of two kinds of eutectic colonies, one is Ni solid solution-CrB eutectic and the other is Ni solid solution-Ni3B eutectic. EBSD pattern analysis revealed that the CrB phase had orthorhombic structure with lattice parameters of a=0.297, b=0.786 and c=0.293 nm, and the Ni3B phase had orthorhombic structure with lattice parameters of a=0.439, b=0.522 and c=0.662 nm. The cuboidal-shaped phase precipitated in the Ni solid solution was found to be the γ' (Ni3Al) phase, which had cubic structure with lattice parameter of a=0.357 nm.

Changes in Mechanical Properties of the Wide-Gap Region Brazed with Various Brazing Temperatures and Times

2005 ◽  
Vol 486-487 ◽  
pp. 113-116
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun
Keyword(s):  
Mechanical Properties ◽  
Fracture Strength ◽  
Filler Metal ◽  
Eutectic Structure ◽  
Metal Powders ◽  
Microstructural Changes ◽  
Binary Eutectic ◽  
Wide Gap ◽  
Low Strength

The microstructural changes and the relations between mechanical properties and additive powder with various brazing temperatures and times were investigated. The IN738 and BNi-3 alloy powders were used as an additive and filler metal powders for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. The wide-gap region brazed with 60wt.% IN738 additive powder had a microstructure consisting of IN738 additive, and binary eutectic of Ni3B-Ni, and (Cr, W)B. As the brazing temperature and time were increased, the size of IN738 additive powder increased to 181µm, which decreased the amount of low strength Ni3B-Ni eutectic structure, thereby increasing the fracture strength of the wide-gap brazed region. Cracks in the brazed region were observed to propagate through the Ni3B-Ni structure, which lowered the fracture strength of the wide-gap brazed region.

TLP Bonding of DS Ni Base Superalloy, GTD-111 Using Mixed Powder of Base Metal and Filler Metal

2006 ◽  
Vol 15-17 ◽  
pp. 894-899
Author(s):  
Bong Keun Lee ◽  
Tae Kyo Han ◽  
Woo Young Song ◽  
C.H. Ye ◽  
Chung Yun Kang
Keyword(s):  
Base Metal ◽  
Filler Metal ◽  
Transient Liquid Phase ◽  
Early Time ◽  
Isothermal Solidification ◽  
Mixing Ratio ◽  
Metal Powders ◽  
Directionally Solidified ◽  
Mixed Powder ◽  
Base Superalloy

The effect of a mixed powder on the wide gap transient liquid phase diffusion bonding of a directionally solidified Ni base superalloy, GTD-111 was investigated. The mixed powder consisted of a mixture of a powdered Ni base filler (GNi-3) and powdered base metal (GTD-111). The range of the base metal powder was 40 to 70wt%. Bonding was performed at a temperature of 1463K, using various holding time. In the case of a lower 50wt%, the base metal powders completely melted and base metal mating at the interface dissolved at an early time, and extent of dissolution of base metal decreased with increasing mixing ratio. Liquid was eliminated by isothermal solidification, which was controlled by the diffusion of B into the base metal. The solids in the bonded interlayer grew epitaxially from the mating base metal inward from the insert metal and the number of grain boundaries formed at the bonded interlayer corresponded with those of the base metal. The finishing time for isothermal solidification was about 74ks. In the case 60wt% and higher, the base metal powders partially melted and remained in the vicinity of bonded interlayer. The solid was formed from the remaining powder and base metal mating at the interface. Finally, the bonded interlayer underwent the poly-crystallization when isothermal solidification was complete. The contents of Al and Ti in the bonded interlayer with a holding of 74ks were equal to that of the base metal.

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.

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 Electroless Ni-P Plating on the Bonding Strength of PbTe Thermoelectric Module Using Silver Alloy-Based Brazing

2020 ◽  
Vol 985 ◽  
pp. 16-22
Author(s):  
Sung Hwa Bae ◽  
Joon Young Choi ◽  
Injoon Son
Keyword(s):  
Bonding Strength ◽  
Filler Metal ◽  
Thermoelectric Module ◽  
Bonding Interface ◽  
Silver Alloy ◽  
Thermoelectric Element ◽  
Thermoelectric Modules ◽  
High Bonding Strength ◽  
Diffusion Barrier Layer ◽  
Electroless Ni

This study investigates a brazing method for manufacturing PbTe thermoelectric modules using a Ag-based filler metal with a melting point of about 650 °C. To improve the bonding strength between the Ag-based brazing layer and the PbTe thermoelectric module, an electroless Ni-P plating layer is formed on the surface of the thermoelectric module as a diffusion barrier layer. The bonding strength of the PbTe thermoelectric module manufactured by the electroless Ni-P plating and Ag-based brazing has a high value of approximately 8.3 MPa. No defects such as pores or cracks were observed at the bonding interface between the thermoelectric element and the brazing layer. Furthermore, because of the high bonding strength of the manufactured thermoelectric module, fractures occur inside the thermoelectric element rather than at the bonding interface. Accordingly, the electroless Ni-P plating and Ag-based brazing method proposed in this study is found to be effective in manufacturing PbTe-based thermoelectric modules with high bonding strength.

A Study of the Effect of Indium Filler Metal on the Bonding Strength of Copper and Tin

2013 ◽  
Vol 6 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Shinji Koyama ◽  
Seng Keat Ting ◽  
Yukinari Aoki ◽  
Ikuo Shohji
Keyword(s):  
Bonding Strength ◽  
Filler Metal
Sign in / Sign up

Export Citation Format

Share Document