Effect of Pr doping on the microstructure, texture and magnetostrictive behavior of polycrystalline Fe81Al19 alloys

Fe
₈₁
Al
₁₉
alloys exhibit excellent mechanical properties and moderate magnetostriction, making it a promising magnetostrictive material. Polycrystalline Fe
₈₁
Al
₁₉
Prx (
x
= 0, 0.05, 0.10, 0.20, 0.30, 0.40) alloys are prepared by arc melting technique. The effect of trace doping of rare-earth element praseodymium (Pr) on the microstructure, texture and magnetostrictive behavior of Fe
₈₁
Al
₁₉
alloys is investigated. The trace doping of Pr transforms the equiaxed crystals into columnar crystals, thus significantly improving the area fraction of favorable η (<100> // rolling direction) texture. With increase of Pr content, a large amount of rich Pr-Al phase is formed at grain boundaries and within the grains, leading to the decrease of Al content and reduction of solid solubility of Pr in the A2 matrix. The magnetostriction of Fe
₈₁
Al
₁₉
Prx alloy increases first and then decreases with increase of the Pr content. Among the prepared alloys, the peak magnetostriction of 159 ppm is obtained at Pr content of 0.10% with 96% enhancement of magnetostriction as compared binary Fe
₈₁
Al
₁₉
alloy. This improvement in magnetostriction is attributed to the solid-solution of trace Pr element and more columnar crystals containing an accurate η texture.