Microstructural Characterization and Phase Development at the Interface Between Aluminum Nitride and Titanium After Annealing at 1300°–1500°C
Abstract:Diffusion couples of aluminum nitride (AlN) and Ti were annealed under an argon atmosphere at temperatures ranging from 1300° to 1500°C for 0.5–36 h. The morphologies, crystal structures, and chemical compositions of the reaction zones at AlN/Ti interfaces were characterized using analytical scanning electron microscopy and analytical transmission electron microscopy. An interfacial reaction zone, consisting of TiN, 2-Ti2AlN, 1-Ti3AlN, α2-Ti3Al, and a two-phase (α2-Ti3Al+α-Ti) region in sequence, was observed in between AlN and Ti after annealing at 1300°C. The α2-Ti3Al region revealed equiaxed and elongated morphologies with and . In the two-phase (α2-Ti3Al+α-Ti) region, α2-Ti3Al and α-Ti were found to satisfy the following orientation relationship: and . The -TiAl and a lamellar two-phase (-TiAl+α2-Ti3Al) structure, instead of 1-Ti3AlN, were found in between 2-Ti2AlN and α2-Ti3Al after annealing at 1400°C. The orientation relationship of -TiAl and α2-Ti3Al in the lamellar structure was identified to be as follows: and . Compared with the reaction zone after annealing at 1400°C, the -TiAl was not found at the interface after annealing at 1500°C. The microstructural development resulting from isothermal diffusion at 1300°C and subsequent cooling at the interface are explained with the aid of the Ti–Al–N ternary phase diagram and a modified Ti–Al binary phase diagram.
Document Type: Research Article
Affiliations: Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan
Publication date: April 1, 2006