Effect of Magnetic Field on Microstructure Evolution during Disorder-Order Transformation in an Fe-Pd Alloy
Effect of Magnetic Field on Microstructure Evolution during Disorder-Order Transformation in an Fe-Pd Alloy
复制标题
磁场对 Fe-Pd 合金无序转变过程中微观结构演化的影响
DOI：
10.2320/matertrans.maw200810
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发表时间：
2008
影响因子：
1.2
通讯作者：
T. Kakeshita
中科院分区：
文献类型：
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作者：
S. Farjami;T. Fukuda;T. Kakeshita
通过磁场作用下的固-固相变来控制显微组织是改善材料性能和设计新材料的一种很有前途的方法。通常，从原子扩散的观点来看，固-固相变可分为两类：无扩散(马氏)相变和扩散相变。众所周知，无扩散和扩散相变的特性都会受到磁场和压力等外场的影响。在马氏体相变的情况下，深入研究了磁场对显微组织的影响。一个著名的例子是铁磁形状记忆合金中磁场驱动的马氏体变异体的重排。在这些合金中，选择磁晶各向异性能量最低的变种通过孪生变形来生长，消耗其他变种，并定量地推导了实现重排的条件。1-4)另一方面，在扩散相变方面，虽然到目前为止已经报道了许多有趣的结果，但磁场对微观结构的影响还没有得到很好的阐明。5-10)考虑到磁场在铁磁形状记忆合金中选择变种的有效性，我们也可以期待在具有大磁晶各向异性的合金中选择性地形成在扩散过程中形成的变种。对于这类材料，Co-Pt和FEPD合金可以作为一种合适的体系。原因如下。CoPT和FEPD中的无序-有序相变是一种典型的扩散相变，由于其大的磁晶各向异性，微结构的形成有望受到磁场的影响。与这种无序-有序转变相关的结构变化是从A1型(立方)无序结构到L10型(四方)有序结构，有序相具有三个晶格对应的变体，并且具有高单轴磁致伸缩的特征
Control of microstructure through solid-solid phase transformation under magnetic field is a promising method to improve the properties and design new materials. In general, solid-solid phase transformations are classified into two groups from a viewpoint of atomic diffusion: diffusionless (martensitic) transformations and diffusional transformations. The characteristics of both diffusionless and diffusional transformations are known to be influenced by external fields such as magnetic field and pressure. In the case of the martensitic transformations, the effects of magnetic field on microstructure have been intensively studied. A well-known example is the rearrangement of martensite variants driven by magnetic field in ferromagnetic shape memory alloys. In these alloys the variant with the lowest magnetocrystalline anisotropy energy is selected to grow consuming others by twinning deformation, and the condition for realizing the rearrangement has been derived quantitatively. 1–4) On the other hand, concerning diffusional transformations, the effect of magnetic field on microstructure has not been so clarified yet although many interesting results have been reported until now. 5–10) Considering the effectiveness of magnetic field on selection of variants in ferromagnetic shape memory alloys, we can also expect a selective formation of a variant which is formed in a diffusive process in alloys with a large magnetocrystalline anisotropy. As for such materials, Co-Pt and FePd alloys can be a suitable system. The reason is as follows. The disorder-order transformation in CoPt and FePd is one of the representative diffusional transformation in which the microstructure formation is expected to be influenced by magnetic field because of their large magnetocrystalline anisotropies. The structure change associated with this disorder-order transformation is from an A1-type (cubic) disordered structure to an L10-type (tetragonal) ordered structure and the ordered phase has three lattice corresponding variants and is characterized by a high uniaxial magneto
通过磁场下的有序热处理实现 L1_0 型 CoPt 变体的选择性形成
DOI：
--
发表时间：
2008
期刊：
Scr. Mater 58
影响因子：
--
作者：
S. Farjami;M. Yasui;T. Fukuda;T. Kakeshita
通讯作者：
T. Kakeshita