The dependence of tensile behaviour of L1₂ compound Al₆₇Ti₂₅Mn₈ on the strain rate at 1173 K

The tensile behaviour of the forged L1₂ compound Al₆₇Ti₂₅Mn₈ was studied as a function of strain rates from 3.34 × 10^-5 s^-1 to 6.68 × 10^-4 s^-1 at 1173 K. The results showed that strain rate has a substantial effect upon the tensile properties, especially the tensile elongation of the alloy. When the rate decreases from 6.68 × 10^-4 s^-1 to 3.34 × 10^-5 s^-1, the yield stress decreases and the tensile ductility increases from 2.8% to 21%. The good high temperature ductility at low strain rates is attributed to dynamic recovery and dynamic recrystallization during deformation. The fractured surfaces of the alloys at various rates are fully or predominantly intergranular, which suggests that the grain boundaries of Ll₂ Al₆₇Ti₂₅Mn₈ are intrinsic weak and/or the slip transfer across the grain boundaries is difficult.