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Stability of an Ordered phase under Rapid Heating

快速加热下有序相的稳定性

基本信息

批准号：
13305043
负责人：
MOHRI Tetsuo
金额：
$ 17.97万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13305043/
关键词：
rapid up-quenching ordering reaction Cluster Variation Method Retro effect Spinodal Ordering Spinodal disordering Phase Field Method Path Probability Method スピノーダルオーダリングスピノーダルディスオーダリング Phase Field法急令 wetting 規則ドメイン規則全不規則変態 /

项目摘要

Down quenching in a common operation employed in materials science and technology communities both to investigate the kinetics of phone transition and to realize new structural and functional properties. In the present study, we focused on the reverse operation, namely the up-quenching operation, and we attempted to clarify the stability and phase transition kinetics of a low temperature ordered phone both theoretically and experimentally. Particular focuses were placed on ; (1) phase transition behavior below an above the spinodal disordering temperature, and (2) detection and interpretation of Retro effect. We first performed the theoretical calculations based on Cluster Variation Method and Path Probability Method and suggested that the spinodal disordering in a common phenomenon for an order-disorder system of first-order transition. Further theoretical studies based on the Phase Field Method clarified the microstructural evolution kinetics of Anti phase boundary during the relaxation process, and by combining with the FLAPW electronic structure calculations, more realistic calculations for the microstructural topology of Anti Phase boundary was performed for Fe-Pd system. The present experimental investigations are classified into two major categories. One is the detection of spinodal disordering temperature for Ni-Mo system and the other is the clarification of the mechanism of Retro effect for Cu-Au system. For the former, anomaly was detected for both the electrical resistivity and the coefficient of thermal expansion when the heating rate is accelerated. For the latter, combined with Laser Microscopy, the evolution and devolution of the surface morphology is carefully observed upon heating and cooling. We concluded that the Retro effect is associated with internal stresses originated from the constraint due to the discontinuity of grain boundaries.

在材料科学和技术领域中采用的常用操作中的向下淬火，既用于研究电话转变的动力学，又用于实现新的结构和功能特性。在本研究中，我们专注于反向操作，即上猝灭操作，我们试图澄清的稳定性和相变动力学的低温有序电话的理论和实验。特别关注的是：（1）低于和高于亚稳无序温度的相变行为，以及（2）Retro效应的检测和解释。我们首先基于集团变分法和路径概率法进行了理论计算，提出了一级跃迁有序-无序系统中普遍存在的失稳现象。基于相场方法的进一步理论研究阐明了弛豫过程中反相界的微观结构演化动力学，并结合FLAPW电子结构计算，对Fe-Pd体系反相界的微观结构拓扑进行了更符合实际的计算。目前的实验研究分为两大类。一个是Ni-Mo体系失稳温度的测定，另一个是Cu-Au体系Retro效应机理的阐明。对于前者，当加热速率加快时，电阻率和热膨胀系数都检测到异常。对于后者，结合激光显微镜，在加热和冷却时仔细观察表面形貌的演变和退化。我们得出的结论是，复古效应是与内部应力源于约束，由于晶界的不连续性。