Stress effect on field-induced detwinning strain hysteresis loops in 5m martensite of Ni49.9-Mn28.5-Ga21.6 alloy
Stress effect on field-induced detwinning strain hysteresis loops in 5m martensite of Ni49.9-Mn28.5-Ga21.6 alloy
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DOI：
10.1016/j.msea.2006.01.109
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发表时间：
2006-11
期刊：
影响因子：
6.4
通讯作者：
L. Hirsinger;N. Creton
中科院分区：
文献类型：
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作者：
L. Hirsinger;N. Creton
本文研究了Ni-Mn-Ga等铁磁形状记忆合金的磁力学行为。本文首次提出了单晶在磁场和机械应力作用下孪晶马氏体薄片重排的原始实验。然后在磁畴的尺度上，即在所研究的耦合现象的相关尺度上建立模型。多尺度方法和不可逆过程的热力学可以定义宏观量，建立自由能，提出变量的演化规律，得到施加在孪晶上的热动力的表达式。通过该模型的构建，得到的力学行为模型只有8个易于测量的附加参数（磁晶各向异性常数、饱和磁化强度、最大变形、初始磁化率等）。
This article deals with the magneto-mechanical behaviour of ferromagnetic shape memory alloys like Ni–Mn–Ga. Original experiments of rearrangement of twinned martensite platelets in a single crystal subjected to a magnetic field and a mechanical stress are first presented. A model is then built at the scale of the magnetic domains, i.e. at the relevant scale for the studied coupled phenomena. The multi-scale approach and the thermodynamics of irreversible processes allow to define the macroscopic quantities, to set up the free energy, to propose the evolution laws of the variables and to obtain the expression of the thermodynamic force which is exerted on twins. From its construction, the model of mechanical behaviour obtained has only eight parameters easily measurable in addition (constant of magnetocrystalline anisotropy, saturated magnetization, maximum deformation, initial magnetic susceptibility, etc.).