화학공학소재연구정보센터
Journal of Materials Science, Vol.35, No.15, 3923-3929, 2000
Microstructural characterization of gamma-TiAl base alloy by electron probe x-ray microanalysis and electron backscatter diffraction
Electron backscatter diffraction (EBSD) and electron probe x-ray microanalysis (EPMA) in combination with x-ray diffraction (XRD) were applied for phase identification of the ternary precipitates and accompanying phases in Ti-49.6Al-1.9Fe alloy after heat treatment at 1400 degrees C followed by furnace cooling. The heat treatment resulted in formation of the duplex structure consisting of equiaxed grains of the gamma phase (AuCu type) and lamellae of the gamma and alpha(2) (Ni3Sn type). The ternary tau(2) (Mn(2)3Th(6) type) phase, containing 21-22 at. % Fe, was revealed on the grain boundaries of the gamma-matrix and lamellae, and is accompanied by alpha(2) precipitates. Different morphologies of the tau(2) + alpha(2) colonies were found to differ in chemical composition, coarse particles being depleted in titanium, and the fine particles enriched in it. The combination of EPMA and EBSD in scanning electron microscopy proved to be very effective in local phase identification of specimens with fine multiphase structure.