1986 Volume 4 Issue 1 Pages 60-66
Solid state bonding is genrally applied to joint of a dissimilar metal which is very difficult to bond by fusion welding techniques.
In this paper a diffusion bonding of aluminum bronze containing Si to austenitic stainless steel has been investigated. The investigations were performed by both method of a direct bonding without insert metal and bonding with insert metals of Cu, phosphor bronze and Ni foils under a restrained condition or a constant bonding pressure, 0.94 MPa. The results obtained as follows; (1) The bonding strength in the insert metal bonding was higher than that in the direct bonding and it was the highest in case of using Ni insert metal among others in the bonding temperature below 890°C. A maximum strength of 410 MPa was obtained at 710°C. (2) In case of using Cu insert metal, the bonding sterngth was much lower comparing to other cases, especially lower than the case of using Ni in the low temperature below 950°C, however, in the temperature of 960°C both bonding strength became almost the same. (3) At the temperature of 960°C and higher than that, the optimum results were obtained with melted down phosphor bronze, it is considered that a liquid phase bonding occurred then. (4) In case of using Ni insert metal, the effect of thickness differences of insert metals ranging between 10 and 60μm on the bonding strength was not recognized extending over all of the bonding temperature used. On the other hand, in the Cu insert metal bonding, the bonding strength in the case of 10μm foil was higher than that of 100μm foil and the strength difference in both foils was from 50 to 100 MPa. (5) The tensile fracture occurred at the boundary interface between the two base metals in the case of the direct bonding, it occurred too in the case of insert metal bonding between aluminum bronze and the insert metals such as Ni or Cu. For phosphor bronze insert metal bonding fracture occurred respectively at three places which are the interfaces between aluminum bronze and the insert metal, between the insert metal and a diffusion layer produced in stainless steel side and between the diffusion layer and stainless steel.