Diffusion Welding of Titanium to Aluminum
1977 Volume 46 Issue 2 Pages 82-89
Details
1977 Volume 46 Issue 2 Pages 82-89
Diffusion welding of titanium to aluminum has been performed. It is an example of the welding between dissimilar metals which form brittle intermetallic compounds in the bonding interface. In order to investigate the important factors which affect the mechanical properties of joint, the microstructure in the bonding zone was examined in detail with several metallographic methods, such as optical micrograph, Knoop hardness test, X-ray analysis and scanning electron micrograph. The results obtained are summarized as follows:
1. The joint strength increased with increasing welding temperature and time. The joints welded for more than 30 min. at 600°C were fractured at aluminum base metals on the tensile strength test.
2. The interlayer which consisted of intermetallic compound Al3Ti was formed in the bonding interface. The thickness of this interlayer increased almost linearly with welding time. The increase in the thickness did not reduce the joint strength up to 10 μm at least.
3. The oxide film on the faying surface of aluminum was considered to be the most important factor which affects the joint strength. That is, the joint strength did not increase sufficiently since the, oxide film inhibited the formation of metallic bond between the base metals.
4. The formation of metallic bond between the base metals proceeded preferentially in the regions where the oxide film was broken by the micro-asperities on the faying surface of titanium.
