High-temperature deformation mechanisms in superplastig ′n-22Al eutectoid

摘要: Abstract The temperature and the stress dependences of steady-state strain-rates in ′n-22Al eutectoid ′ere studied by tensile creep testing using double shear type specimens a normali′ed ( τ G ) range ~5 × 10 −7 to −3 . dependence strain-rate revealed three distinct regions ′ith exponents 0.87 ± 0.12, 1.99 0.15 3.73 0.17. activation energy for deformation obtained I II ′as identified as that grain-boundary diffusion ′hile found region III approximately e′ual self-diffusion value. experimental results employed obeyed follo′ing phenomenological e′uation, γ ggkT D b Gb = A( d m n 1 α From values parameters , A mechanisms are identified. Dislocation climb Coble be controlling respectively. present close agreement predictions based on Ball-Hutchison model superplasticity, models grain boundary sliding yield about 250 times values.