Abstract
The effect of alternating stress, which was superimposed on the bonding pressure, on the bonding strength of alumina-copper joint was investigated. Alumina-copper joint with a thin aluminum interlayer deposited in the vacuum was performed at temperatures above 773 K in argon gas at a pressure of 0.4 MPa under the alternating stress.
The main results obtained are as follows:
(1) At each bonding temperature, the strength of joint increased with increasing time and reached a peak strength and then decreased with increasing time.
(2) The addition of alternating stress on the bonding pressure has the effect to increase the peak strength and to promote the bonding process.
(3) Apparrent activation energy for the bonding process is calculated to be about 49 kJ/mol.
(4) A reasonable explanation for improving the bonding strength due to the alternating stressing can be made on basis of the reduction in thermal stress due to local fatigue deformation.
(5) Bonding reaction proceeding during heating up has no significant effect on the experimental results.
