Microstructure and properties of directly bonded joint of A6061 aluminum alloy to SUS316 stainless steel: study on diffusion bonding of aluminum alloy to stainless steel (report 1)

摘要

Microstructural analyses and tensile testing of directly diffusion-bonded joints of A6061 to SUS316 were conducted in order to evaluate the joinability of aluminum alloy to stainless steel. Diffusion bonding of A6061/SUS316 was carried out at 723-848 K for 0.3-9.0 ks applying 9.8 MPa in vacuum. SEM observation revealed that the reaction layer was formed at the A6061/SUS316 interface. The intermetallic compounds such as Fe{sub}2Al{sub}5 and FeAl{sub}3 were identified in the reaction layer. It was elucidated that the reaction layer growth could be expressed by parabolic growth law, and that the apparent activation energy for the reaction layer growth was 187 kJ/mol. The tensile strength of A6061/SUS316 joint was risen up to about 200 MPa by maintaining the reaction layer thickness at around 1-2μm. The fracture modes shifted from the interfacial fracture to the brittle fracture in reaction layer with increase in the reaction layer thickness.