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%AI polycrystals at a total strain of 1.0%. The amount of strain recovery in Fe-Al polycrystals showed a maximum at 25,0at% 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%AI 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.