Morphology and reaction kinetics of the interface phase formed by diffusion bonding micron-thick Mo-Al rolled foils

Mo and Al rolled foils with 20 and 60μm in thickness respectively, were diffusively bonded at 873-913 K for 40-240 min. Primary phase formed during Mo-Al interfacial reaction is Al₈Mo₃, which nucleated in Mo foils and grew up with breaking the covering Mo layer. With diffusion bonding time increasing, Al₈Mo₃, Al₅Mo and Al₁₂Mo layers presented between Mo and Al, and Al₄Mo appeared between Al₈Mo₃ and Al₅Mo after bonding at 913 K for 240 min. Kinetics analysis indicated that the incubation period of primary phase decreased from 52 to 34.5 min when bonding temperature increased from 873 to 913 K, the pre-exponential factor and diffusion activation energy for an Al atom in the phases produced by Mo-Al reaction are 4.61×10^-2cm²/min and 0.98 eV respectively, correspondingly, those for an Al atom in Mo foils are 2.05×10^-2cm²/min and 1.48 eV.