Pseudoelastic Behavior of Fe–Al Polycrystals

摘要

Pseudoelastic behavior of Fe–Al polycrystals at room temperature was examined focusing on Al concentration, the crystallographic texture and the grain size. Perfect pseudoelasticity derived from the reversible motion of 1/4 ?111? superpartial dislocations dragging the anti-phase boundaries (APB) took place in Fe–25.0at%Al polycrystals at a total strain of 1.0%. The amount of strain recovery in Fe–Al polycrystals showed a maximum at 25.0 at% Al and the deviation from the concentration led to a decrease in strain recovery. The backward stress due to APB and dislocation configuration in Fe–Al alloys was closely related to the dependence of the pseudoelasticity on Al concentration. The pseudoelastic behavior of Fe–25.0at%Al polycrystals depended strongly on the loading axis, which could be accounted for in terms of the Taylor factor. Moreover, recovery strain of Fe–23.0Al polycrystals increased with increasing average grain size suggesting that the grain boundaries suppressed the forward and backward motion of the superpartials and were harmful for the pseudoelasticity.