ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Effect of Initial Microstructure of Intermediate Material on Superplastic Diffusion Bonding of Duplex Stainless Steel
H. KokawaT. SuzukiT. Kuwana
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1995 Volume 35 Issue 10 Pages 1291-1297


A duplex stainless steel was diffusion-bonded in a vacuum using duplex stainless steel intermediate materials with different initial microstructures. The effects of bonding temperature, pressure, and microstructure of the intermediate material on the soundness of bonding interface region and bonding strength were examined. The number of voids at the bonding interface reduced with increases in bonding temperature and pressure, and with a decrease in average grain size of the intermediate material. When the intermediate material had a microduplex structure, void-free bonding interface was achieved even in a specimen bonded at a temperature as low as 1173K and at a pressure as low as 0.7 MPa. Tensile tests on the joints revealed that the bonding strength of void-free specimen was not less than the tensile strength of base material. A TEM study suggested that superplastic deformation of intermediate materials due to sliding at ferrite/austenite boundaries and ferrite/ferrite grain boundaries can contribute greatly to the bonding.

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