INTECIN   20395
INSTITUTO DE TECNOLOGIAS Y CIENCIAS DE LA INGENIERIA "HILARIO FERNANDEZ LONG"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Transient liquid phase bonding of carbon steel tubes using Cu interlayer: characterization and comparison with amorphous Fe B Si interlayer bonds
Autor/es:
N.DI LUOZZO; B. DOISNEAU; M. BOUDARD; M. FONTANA; B. ARCONDO
Lugar:
Torino
Reunión:
Simposio; 20th International Symposium on Metastable, Amorphous and Nanostructured Materials (ISMANAM 2013); 2013
Resumen:
In the present work the transient liquid phase bonding process [1] was performed to join seamless carbon steel tubes using commercially pure Cu interlayer. The structural and mechanical characteristics of the resulting bond are compared with those achieved using amorphous Fe?B?Si interlayer, under the same process parameters: a holding temperature of 1300 ºC, a holding time of 7 min and an applied pressure of 5 MPa. The joined tubes microstructures were characterized by direct - scanning electron microscopy - and reciprocal space - electron backscatter diffraction - observations. Chemical analysis was performed by energy dispersive spectrometry (EDS) and using electron probe microanalysis. Whereas the amorphous Fe?B?Si interlayer leads to a completion of the bonding process over the whole bonding area, the bond performed using Cu interlayer achieved the completion of the bonding process only partially (see the Cu mapping in fig.1). As the Cu is a cementite promoter [2], the amount of cementite coexisting with ferrite grains is higher in the diffusion affected zone (DAZ) ? corresponding to the higher concentration of Cu ? as compared with the heat affected zone (HAZ) and the base metal (BM). An opposite effect is observed when using Fe?B?Si interlayer due to the fact that the cementite is unable to form in Si enriched zones [3] ? the microstructure at DAZ presents only ferrite grains. Tensile tests show that the joined tubes using Cu interlayer failed at the bond ? in contrast with the joined tubes using Fe?B?Si interlayer that failed away from the bond, at the HAZ ? but attained 94% of the ultimate tensile strength of the BM, in the as-bonded condition. Microhardness profiles across the bonding zone are in agreement with the observed microstructures at the different zones of the bond region.   [1]    D. S. Duvall, W. A. Owczarski, D. F. Paulonis, Welding Journal 204 (1974), 203. [2]    R. A. Gonzaga, Materials Science & Engineering A 567 (2013), 1. [3]    H. Bhadeshia, R. Honeycombe, Steels: Microstructure and Properties (2006), 223.