Formation of ODS L12–(Al,Cr)3Ti by mechanical alloying

Recently, it has been shown that the addition of a certain amount of ternary alloying elements like Cr transforms the tetragonal D022-structure of Al3Ti to the cubic L12-structure with higher crystal symmetry. However, this attempt of overcoming its brittleness at ambient temperature results in relatively poor creep strength at high temperatures. Therefore, the methods of mechanical alloying and high energy ball milling were used to prepare the ternary (Al,Cr)3Ti L12-intermetallic compound additionally strengthened by small volume fractions of incoherent Y2O3 dispersoids. The development of the microstructure and the phase formation were investigated by X-ray diffraction and transmission electron microscopy (TEM). First results on consolidated bulk samples are presented, indicating the possibility of producing oxide dispersion strengthened (ODS) intermetallics from mechanically milled powders.