兰州大学机构库 >土木工程与力学学院
铁磁形状记忆合金马氏体变体重取向及其多场耦合行为研究
Alternative TitleMartensite Variants Rearrangement and Multi-Field Coupling Behavior of Ferromagnetic Shape Memory Alloys
李芳
Thesis Advisor王省哲
2011-12-20
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword铁磁形状记忆合金 磁致应变 马氏体变体重取向 多场耦合行为 磁畴与微结构
Abstract首先,基于宏观连续介质热力学的张量表述形式,本文建立了一个宏观重取向动力学模型,来描述铁磁形状记忆合金在力-磁-热多场耦合下的马氏体变体重取向行为。 其次,为了解释上述的实验现象,我们建立了一个描述铁磁形状记忆合金内部磁畴结构特征与变化的微磁热力学统计模型。模型给出了各个马氏体变体中磁畴内部的总势能表述,通过定义磁畴间的Gibbs自由能差为驱动磁畴壁移动的广义驱动力以及基于统计学方法,获得了马氏体变体内各个磁畴体积分数的表达形式,合理解释了不同马氏体变体内磁畴微结构变化机理和实验现象。 再次,我们从细观角度建立了一个细观热力学模型来描述铁磁形状记忆合金在力-磁耦合作用下的马氏体变体重取向行为。 最后,我们将马氏体变体内部磁畴结构变化的热力学统计学模型与细观力学相结合,构建了一统一的广义细观热力学模型。
Other AbstractFirstly, a kinetics model describing macroscopic behavior of martensitic variants rearrangement in FSMAs is proposed, which is based on a tensor description of thermodynamic continuum mechanics taking into account magneto-thermo- mechanical coupling on the MVR process. Secondly, an analytical model based on the statistical method and energy minimization theory of micro-magnetics is presented in the present work to capture the magnetic domain behavior of ferromagnetic shape memory alloys during the MVR. The difference between the Gibbs free energy of magnetic domain in each martensite variant is defined as the general driving force for the domain wall motion. Based on the proposed micro-mangetic statistical model, the volume fractions of magnetic domains of the different martensite variants are obtained and the mechanism of the variation of magnetic domain is revealed which further explains the experimental observations successfully. Thirdly, a micromechanical model is proposed to describe the magneto- mechanical behaviors of FSMAs during the MVR process. We treat the MVR of FSMAs as one phase of martensite variant being a inclusion inside of another phase of martensite variant. Lastly, by combining the thermodynamic statistical model of micromagnetics for describing the evolution of the magnetic domains with the micromechanics theory, a generalized micromechanical-base thermodynamic model is proposed.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/225916
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
李芳. 铁磁形状记忆合金马氏体变体重取向及其多场耦合行为研究[D]. 兰州. 兰州大学,2011.
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