Microstructure and Mechanical Properties of Inconel 738LC Joint by Wide Gap Brazing Using Inconel 718

Document Type : Research Article

Authors

1 Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Hafez Ave., Tehran, Iran

2 امیرکبیر-معدن و متالورژی

3 Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran

4 شریف-مهندسی و علم مواد

Abstract

In this research, Inconel 738LC as the base metal was joined by wide gap brazing using the mixture of Inconel 718 as high-temperature particle and BNi-2 as low-temperature particle. By using Inconel 718, the brazing temperature can be increased and porosity reduced significantly due to higher melting point temperature than the base metal. The effect of mixture ratio on the microstructure and the mechanical properties was studied. The amount of the low-temperature particle in the mixture was 30, 40, and 50 percent. By decreasing the low-temperature particle ratio, the amount of eutectic phase and the blocky boride in the solid diffusion zone decreased markedly. The joint width increased by increasing the amount of low-temperature particles. There were two distinct regions in the joint/base interface. Due to the diffusion of boron into the base, adjacent to the joint, the grain boundary melted and created a region including both the isothermal solidification zone and solid diffusion zone. By getting away from the joint, the content of boron reduced by the grain-boundary diffusion. It was observed that aging did not have a significant effect on the amount and distribution of eutectic phases and blocky borides, however, the morphology of these phases changed slightly. Moreover, aging had a small effect on hardness making the hardness of different phases more uniform.

Keywords

Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 52, Issue 10
January 2021
Pages 2629-2646

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