Strong, Ductile and Low-Field Magnetostrictive Alloys Based on Fe-Ga

这项研究探讨了合金化添加和晶体结构如何影响Fe和Fe-Ga基合金的磁致伸缩。用单晶和定向凝固多晶合金研究了不含d壳层电子的合金元素、填充d壳层的合金元素和部分填充d壳层的合金元素的影响。用Fe-27.5a%Ga合金研究了晶体结构的影响，该合金可以存在于“有序(Bcc)、DO19有序(六方)、L12有序(Fcc)和无序bcc结构中。这项工作的另一个主要目标是研究一种低成本的热机械加工方法，以低成本生产[001]织构的Fe-Ga基多晶合金。加工方法包括冷/温变形和再结晶。评估了不同工艺参数对Fe-Ga合金织构性质的影响，以及织构演化的控制机制。通过在扫描电子显微镜中利用取向成像显微镜(OIM)研究加工过程中织构的演化，确定了导致[001]织构的工艺条件。这笔赠款将使人们更好地了解铁基合金的磁致伸缩，以及用于传感器和执行器应用的低成本和高磁致伸缩合金。这笔赠款还将加强研究生和本科生的教育、培训和招聘活动。

This grant explores how alloying additions and crystal structure influence magnetostriction in Fe and Fe-Ga based alloys. The influences of selected alloying elements with no d-shell electrons, with filled d-shells, and with partially filled d-shells are examined using single crystals and directionally solidified polycrystalline alloys. The influence of crystal structure is examined using a Fe-27.5 a% Ga alloy that can exist in a"-ordered (bcc), DO19-ordered (hexagonal), L12-ordered (fcc), and disordered-bcc structures. Another principal goal of this work is to examine a low cost thermomechanical processing approach to produce [001] textured Fe-Ga based polycrystalline alloys at low cost. The processing approach involves cold/warm deformation and recrystallization. An assessment of the influence of the amount of different process parameters on the nature of texture obtained in selected Fe-Ga alloys, and the mechanisms controlling the evolution of texture will be made.The processing conditions that result in [001] texture are identified through a study of texture evolution during processing using Orientation Imaging Microscopy (OIM) in an SEM. The grant will result in an improved understanding of magnetostriction in Fe based alloys, and low cost and highly magnetostrictive alloys for use in sensor and actuator applications. The grant will also enhance the graduate and undergraduate educational, training, and recruitment activities.