Magnetostrictive Body Centered Iron Base Alloys

包括一种新的场诱导缺陷性质张量的晶体固体中缺陷的热力学模型解释了Fe-Al和Fe-Ga合金中超磁致伸缩的已知变化。具体地说，该模型表明，具有四方对称性的次近邻置换对是造成这种效应的原因。这些研究旨在通过测量松弛和非松弛磁致伸缩、弹性和磁各向异性常数以及晶格常数来自洽地确定模型参数。为了推广这个模型，研究将扩展到Fe-C-Al和Fe-C-Ga，以及可能包含四方对称缺陷对的其他合金。这些研究将使人们对体心铁基合金的显著磁致伸缩有一个基本的了解。它们将至少使过剩磁致伸缩系统化，并最大限度地建立具有显着磁致伸缩的新型合金的开发标准。具有高达.000200的磁致伸缩的材料具有重要的技术价值。这些研究将确定体心立方铁基合金的磁致伸缩的性质，并为寻找更多的磁致伸缩合金建立标准。***

0095166WuttigA thermodynamical model of defects in crystalline solids which includes a novel field induced defect property tensor accounts for the known variation of the excess magnetostriction in Fe-Al and Fe-Ga alloys. Specifically, the model suggests that next nearest neighbor substitutional- substitutional pairs of tetragonal symmetry are responsible for the effect. The studies are directed to determine the model parameters self-consistently through measurements of the relaxed and unrelaxed magnetostrictive, elastic and magnetic anisotropy constants as well as lattice constants. In an effort to generalize the model the studies will be extended to Fe-C-Al and Fe-C-Ga and possibly additional alloys containing defect pairs of tetragonal symmetry. The studies will lead to a basic understanding of the significant magnetostriction in body-centered iron-base alloys. They will at minimum systematize the excess magnetostriction and maximally establish criteria for the development of novel alloys with a significant magnetostriction. %%%Materials with a magnetostriction as large as .000200 are of significant technological interest. The studies will identify the nature of the magnetostriction in body centered cubic iron base alloys and establish criteria for the search of additional magnetostrictive alloys. ***