Mathematical Modeling and Experimental Investigations of Isothermal Solidification during Transient Liquid Phase Bonding of Nickel Superalloys

2006 ◽  
Vol 15-17 ◽  
pp. 882-887 ◽  
Author(s):  
Muhammad A. Arafin ◽  
Mamoun Medraj ◽  
Daniel P. Turner ◽  
Philippe Bocher
Keyword(s):  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Isothermal Solidification ◽  
Holding Time ◽  
Inconel 625 ◽  
Experimental Investigations ◽  
Transient Liquid Phase Bonding ◽  
Holding Period ◽  
Nickel Base ◽  
Time Required

Mathematical model, based on Fick’s second law of diffusion, was used to predict the time required to complete isothermal solidification and to determine the effect of process variables during the transient liquid phase bonding of Inconel 625 and 718 superalloys with nickel based brazing filler alloy BNi-2. Experimental investigations were carried out in the range of 1325 – 1394K to verify the model and the predicted times were in excellent agreement with the experimentally determined values. The obtained activation energies for diffusion of boron were very close to the ones reported for other nickel base polycrystalline superalloys; however, it was observed that the time required for complete isothermal solidification are significantly less than that of other nickel based superalloys with different nickel based brazing filler alloys. Because of this advantage, these combinations of base and filler alloys are expected to replace other currently used ones. Further, significant reduction of holding time was observed with increasing brazing temperature and with decreasing joint gap. The composition of the joints at the end of holding period, when the holding time was not sufficient to complete isothermal soldification, has been determined in order to predict the amount of brittle eutectic phases in the final joint microstructures.

Joining of NiAl to Nickel-Base Alloys by Transient Liquid Phase Bonding

1998 ◽  
Vol 552 ◽  
Author(s):  
Z. A. M. Abdo ◽  
Y. Guan ◽  
W. F. Gale
Keyword(s):  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Isothermal Solidification ◽  
Conventional Technique ◽  
Microstructural Development ◽  
Second Phase ◽  
Gap Technique ◽  
Wide Gap ◽  
Nickel Base ◽  
Time Required

ABSTRACTA transmission and scanning electron microscope investigation is undertaken to study microstructural development during transient liquid phase (TLP) bonding of NiA1 to Ni-base substrates. The bonds were produced through a conventional technique employing a Cu foil interlayer or a widegap technique using a composite preform containing powders of NiAl and Cu. The time required for completion of isothermal solidification was greatly reduced in wide-gap bonds as compared to conventional bonds. Microstructural features of conventional TLP bonds of polycrystalline-NiAl/Ni were controlled by the ratio of Al: Cu across the joint. The precipitation of the a phase encountered in polycrystalline- NiAl/Martin Marietta 247 superalloy (MM247) bonds was suppressed in wide-gap bonds of single crystal-NiAl(Hf) and MM247. In general, the extent of second phase precipitation, in the asbonded condition, was greatly reduced by the use of the wide-gap technique. However, extensive precipitation of HfC and W-rich phases was observed after post-bond heat treatments.

Effect of Bonding Pressure on Transient Liquid Phase Bonding Joint Microstructure and Properties of T91/12Cr2MoWVTiB

2010 ◽  
Vol 97-101 ◽  
pp. 107-110 ◽  
Author(s):  
Si Jie Chen ◽  
Si Jing Guo ◽  
Feng Liang
Keyword(s):  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Optical Microscope ◽  
Isothermal Solidification ◽  
Transient Liquid Phase Bonding ◽  
Bonded Joints ◽  
Electron Microscopic ◽  
Bonding Pressure ◽  
Scanning Electron Microscopic ◽  
Microscopic Techniques

T91/12Cr2MoWVTiB was bonded by transient liquid phase bonding process with different pressures, one commercial FeNiCrSiB was used as the interlayer. The microstructure and components distribution of the bonded joints were examined by optical microscope and scanning electron microscopic techniques. Furthermore, the properties of the joints were also tested. The results indicate that with the increase of the pressure – from 2 MPa to 6 MPa – the microstructures and mechanical properties were improved, and more similar to those base alloys. A theoretical study also revealed that the isothermal solidification complication time can be shorter, because the maximum liquid width was reduced with the existence of pressure.

scholarly journals Transient Liquid Phase Bonding of Ti-6Al-4V and Mg-AZ31 Alloys Using Zn Coatings

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 769 ◽  
Author(s):  
Abdulaziz AlHazaa ◽  
Ibrahim Alhoweml ◽  
Muhammad Shar ◽  
Mahmoud Hezam ◽  
Hany Abdo ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Microstructural Analysis ◽  
Transient Liquid Phase ◽  
Isothermal Solidification ◽  
Uniaxial Pressure ◽  
Transient Liquid Phase Bonding ◽  
Vacuum Furnace ◽  
Joint Region ◽  
Ductile Fractures ◽  
Zinc Coatings

Ti-6Al-4V and Mg-AZ31 were bonded together using the Transient Liquid Phase Bonding Process (TLP) after coating both surfaces with zinc. The zinc coatings were applied using the screen printing process of zinc paste. Successful bonds were obtained in a vacuum furnace at 500 °C and under a uniaxial pressure of 1 MPa using high frequency induction heat sintering furnace (HFIHS). Various bonding times were selected and all gave solid joints. The bonds were successfully achieved at 5, 10, 15, 20, 25, and 30 min. The energy dispersive spectroscopy (EDS) line scan confirmed the diffusion of Zn in both sides but with more diffusion in the Mg side. Diffusion of Mg into the joint region was detected with significant amounts at bonds made for 20 min and above, which indicate that the isothermal solidification was achieved. In addition, Ti and Al from the base alloys were diffused into the joint region. Based on microstructural analysis, the joint mechanism was attributed to the formation of solidified mixture of Mg and Zn at the joint region with a presence of diffused Ti and Al. This conclusion was also supported by structural analysis of the fractured surfaces as well as the analysis across the joint region. The fractured surfaces were analyzed and it was concluded that the fractures occurred within the joint region where ductile fractures were observed. The strength of the joint was evaluated by shear test and found that the maximum shear strength achieved was 30.5 MPa for the bond made at 20 min.

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