Deformation mechanisms and slip transfer in a Ti44Al2Mo alloy

The dislocation configurations produced by room temperature deformation of a Ti44Al2Mo alloy have been analysed, and the ductility and strength of the alloy have been related to the active deformation modes. The presence of three phases with crystal structures L10, B2 and DO19 has been confirmed and their distribution and sizes varied as a function of heat treatment. After deformation, the very deformable L10 structure is characterized by large densities of ordinary 12〈110〉 dislocations and deformation twins with a much lower density of superdislocations. The B2 phase has been confirmed to deform both by 〈100〉 and dissociated 〈111〉 superdislocations on {110} planes. The 〈100〉 {110} system is always seen as pile-ups producing planar slip due to the presence of a fine “ω”-type precipitation. Finally, the hexagonal DO19 phase shows very low dislocation activity and always consists of 〈1120〉{0001} due to the limitations imposed by the compatibility of deformation between the different phases.