Texture formation under rolling and primary recrystallization in Fe86Ga14 alloy

Abstract

Fe-Ga alloys possess the increased magnetostriction in comparison with the traditional magnetostrictive materials Fe-Co and Fe-Al and have a number of advantages over magnetostrictive materials based of rare earths elements. In literature, much attention is paid to composition Fe 81 Ga 19 , as this alloy possesses the greatest magnetostriction in one-phase area. Important condition for attainment of the best functional properties in this material is creation of certain crystallographic texture. However, the substantial difficulty at manufacture of samples and wares consists in a high brittleness of alloy at such content of gallium, for this reason the features of formation of crystallographic texture at deformation and recrystallization in this alloy are studied poorly. In this work, the attempt to study influence of various modes of rolling and annealing on structure and magnetic properties of Fe-Ga alloy with the smaller content of Ga is made. The structure and texture of primary recrystallization were studied by means of an electron back-scattering diffraction, besides field dependences of magnetization were measured. The amount of grains with the direction of easy magnetization in different samples was estimated by the value of magnetic induction at a defined value of magnetic field on a magnetization curve. The values of magnetostriction increased with increase of volume fraction of the components including the direction of easy magnetization of iron-gallium alloy. Absolute values of magnetostriction did not exceed 50 ppm that is at the level of values for traditional materials, but lower than for Fe 81 Ga 19. Plastic deformation by hot and, especially cold rolling causes great difficulties in connection with a high brittleness of alloy even with the lower value of gallium concentration. Therefore, it is necessary to find new methods of a plastic deformation of alloy or to add the chemical elements improving plastic properties of material.

Prospects of Using Fe-Ga Alloys for Magnetostrictive Applications at High Frequencies

“…It should be noted that the creation of a texture of this type in a bcc alloy is a rather difficult task. In recent years, attempts have been made to actively solve this problem by studying the mechanisms of texture formation in Fe-Ga [53,56] and the selection of deformation and recrystallization parameters [52,53,55,[57][58][59][60][61][62][63][64][65]. In terms of technology, there are two approaches to creating desirable texture in Fe-Ga sheets.…”

“…For this reason, an alternative direction is being developed, namely, the creation of the necessary crystalline texture due to primary recrystallization, which does not lead to the formation of large grains [53,54,58,59,62,63,65,78]. The main problem with this approach is the much weaker <100>//RD (rolling direction) texture compared to secondary recrystallization.…”

The influence of microalloying and heat treatment on the structure and properties of Galfenol with high gallium concentration

“…Низкотемпературные диффузионно-контролируемые фазовые превращения в этой системе затруднены, что способствует сохранению при комнатной температуре высокотемпературных фаз, образовавшихся при кристаллизации из расплава [4]. Практически во всех публикациях отмечается, что наилучшие функциональные свойства в Галфенолах достигаются при содержании около 19 или 27 ат.% Ga, однако эти свойства зависят от режимов обработки сплавов [5] и могут быть улучшены за счет микролегирования редкоземельными элементами [1-3, 6 -8].…”