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Diffusion Bonding of FGH 98 and CoCrNi-Based Medium-Entropy Alloy: Microstructure Evolution and Mechanical Tests

Authors :
Jiangtao Xiong
Shiwei Li
Zhaoxi Li
Yipeng Chen
Yajie Du
Jinglong Li
Jihong Dong
Source :
Crystals, Vol 11, Iss 1158, p 1158 (2021), Crystals; Volume 11; Issue 10; Pages: 1158
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

The superalloy FGH98 was successfully diffusion bonded (DB) with medium-entropy alloy (MEA) Al3Ti3(CrCoNi)94 using pure Ni as the interlayer at a temperature range of 1050–1170 °C for 1 h under 5 MPa. The microstructure and mechanical properties of joints were investigated. The diffusion bonding seam was composed of an interlayer zone (IZ) and two diffusion-affected zones (DAZ). The IZ and DAZ beside the FGH98 consisted of cubic Ni3(TiAl)-type γ′ phases due to the diffusion of Ti and Al atoms. Meanwhile, the DAZ adjacent to the MEA consisted of spherical γ′ phases. Both of the γ′ phases with different morphology kept the coherent relationship with the matrix. Moreover, increase of bonding temperature led to the morphology of interlayer γ′ phase to transform from sphere to cube. Due to the strengthening effect of a mass of γ′ phase distributed evenly in IZ and the DAZ beside the FGH98, the microhardness and Young’s modulus of these two zones were higher than that of DAZ near the MEA. The maximum shear strength of DB joint, 592 MPa, was achieved in the joint bonded by 1150 °C, which was the typical ductile fracture feature confirmed by the shear dimples.

Details

ISSN :
20734352
Volume :
11
Database :
OpenAIRE
Journal :
Crystals
Accession number :
edsair.doi.dedup.....d911aaaaac437c1a41fe28cfc17f1545
Full Text :
https://doi.org/10.3390/cryst11101158