Mechanical properties of nanocrystalline TiAl-X and TiAl₃-X prepared by mechanical alloying and sintering

Production of intermetallic materials in the systems TiAl-X and TiAl₃-X (X = Cr, Mn, Fe) has been achieved by means of mechanical milling and sintering techniques. The produced materials have grain sizes in the nano and microscale depending on the material and processing variables. The average grains size range between 30 and 280 nm. Sintered materials in the TiAl-X system are constituted by the γ and the α₂ phases while the Al₃Ti-X alloys are formed only by the cubic L1₂ phase. Compression tests are performed to evaluate their mechanical properties as a function of temperature and grains size. In all cases yield stresses higher that 1 GPa are obtained together with a ductility that depends upon temperature and grains size. No ductility is found for the smallest grains sizes tested (30 nm).