日本金属学会誌

J. Japan Inst. Metals, Vol. 40, No. 1 (1976),
pp. 96-103

Study on Diffusion Bonding of Metals

Ichiro Kawakatsu1 and Seiji Kitayama2

1College of Science & Engineering, Aoyama Gakuin University, Tokyo
2Graduate School, Aoyama Gakuin University, Tokyo

Abstract:

Metallographical phenomena among many factors which control weldability on diffusion bonding has been investigated. Combinations of the base metals were classed into three types; the solid solution type, two-phase type, and intermetallic compound type. Diffusion bonding was carried in the hydrogen atmosphere using several bonding pairs such as Cu-Ni, Cu-Ag, Cu-Al and Fe-Al prepared from cold rolled sheets. Influence of the bonding temperature and time on bonding strength was investigated and the microstructure at the interface was observed.
The results obtained were as follows.
(1) Minimum bonding temperature exists in the neighbourthood of softening temperature of one of two base metals. Especially, in the solid solution type, the bonding strength increased at the softening temperature of one of two base metals.
(2) The increasing process of initial bonding strength is considered as a transient phenomenon from recovery to recrystallization with stored energy and depends on the bonding temperature and time, satisfying Arrhenius' equation.
(3) Bonding strength depends on softening of base metals and alloying at the interface above the recrystallization temperatures of base metals.
(i)\phantom{ii }In the case of the solid solution type, the bonding strength increases with the rise of the bonding temperature and time.
(ii)\phantom{i }In the case of Cu-Ag joints, the effect of bonding conditions is not very large, but the bonding strength increases rapidly after 30 min heating at 700°C.
(iii) In the case of the intermetallic compound type, the alloy layer increases in thickness and the bonding strength deteriorates in Fe-Al joints rapidly above the recrystallization temperature.
(4) Bonding interface tends to disappear as time elapsed above the recrystallization temperature of both base metals of the solid solution type, but it is retained as an interfacial boundary in the case of the two-phase type and intermetallic compound type.


(Received 1975/06/27)

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