FABRICATION OF TIAL MATRIX COMPOSITE SHEETES WITH CONTROLLED MICRO-LAMINATED ARCHITECTURE BY A SOLID-LIQUID REACTION

A feasible method has been successfully developed to manufacture fully dense TiAl matrix composite sheets with unique multi-layered architecture by employing multi-step reaction annealing of the hot-pressed (TiB/Ti)-Al laminates. The TiAl matrix composites displayed a novel layered structure, composing of alternating layers of equiaxed gamma-TiAl layer, fully lamellar alpha(2)-Ti3Al/gamma-TiAl layer and TiB-rich layer which was actually TiB whisker stacking layer. It is worth pointing out that the multi-layered composites showed the enhanced high-temperature tensile properties, in particular for 750 degrees C, the yield strength (alpha(y)) was much higher than that of monolithic TiAl prepared by the reaction annealing of Ti-Al laminates. Consequently, the unique micro-laminated TiB2-TiAl composite sheets have potential for light-weight high-temperature structural application.