Microstructural evolution and domain structure of cobalt particles precipitated in a cooper matrix

本课题组揭示了铜钴合金中的析出行为受钴原子/团簇之间的磁性相互作用的影响。由于迄今积累的系统工作很少，对这一现象的细节和基本认识尚不清楚。本研究包括以下几个部分：(1)外加磁场对合金样品的影响的电子显微镜研究，(2)研究磁畴结构与磁性能关系的磁测量，(3)考虑磁场对Co粒子形成影响的蒙特卡罗模拟，以及(4)磁畴结构的洛伦兹显微镜。施加磁场加速了溶质的析出，尽管粒子的形状没有受到影响。场的影响在降水后期表现得更为明显。析出物的相干-非相干转变的临界尺寸可能受到轻微的影响。合金试件的磁矩受试件微观组织的影响。含Co团簇的样品表现出随场的存在而变化的M-T曲线。非共格共沉淀物由多个磁畴组成，以降低静电能量。

The present research group revealed that the precipitation behavior in a Cu-Co alloy is affected by the magnetic interaction between cobalt atoms/ clusters. Since few systematic works have been accumulated so far, details and fundamental understanding of the phenomena has not obtained yet. The present study consists of the following parts ; (1) TEM study of the influence of the magnetic field externally applied to the alloy specimen, (2) magnetic measurements to investigate the relationship of the magnetic domain structure and magnetic property, (3) the Monte Carlo simulation to consider the influence of the field to the Co-particle formation and (4) Lorentz microscopy of the domain structure.The precipitation of the solute was accelerated by applying the magnetic field, although the shapes of the particles did not receive the influence. Teh influence of the field more explicitly appeared at the later stage of the precipitation. The critical size to coherent-incoherent transition of the precipitate is likely to receive slight influence. The magnetic moment of the alloy specimen was affected with the microstructure of the specimen. The specimen containing Co-clusters shows a M-T curve dependent of the existence of the field. An incoherent Co-precipitate comprised multiple magnetic domains to reduce the electrostatic energy.