Modelling of rearrangement yield surface under biaxial magnetic field in Ni-Mn-Ga shape memory alloys
Modelling of rearrangement yield surface under biaxial magnetic field in Ni-Mn-Ga shape memory alloys
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DOI：
10.3233/jae-2006-732
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发表时间：
2006
影响因子：
0.6
通讯作者：
N. Creton;L. Hirsinger
中科院分区：
文献类型：
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作者：
N. Creton;L. Hirsinger
抽象的。提出了Ni-Mn-Ga铁磁形状记忆合金场致应变的预测模型。模拟了双轴磁场和机械应力对Ni-Mn-Ga单晶马氏体重排的作用。模拟了起始重排的屈服面。它们显示了施加的机械应力如何帮助或反对施加的磁场，使重排更容易或更难。结果与Mullner等人[8]描述旋转磁场作用的实验完全一致。关键词：磁-机械耦合，形状记忆合金，模型1。引言在寻找新的活性材料，铁磁形状记忆合金（FSMA），如Ni-Mn-Ga有一个突出的地位，由于他们的能力，以开发应变更重要的比conventionalactive材料，如压电和磁致伸缩。与经典的形状记忆合金相反，它们能够在外加磁场下非常迅速地发展这种应变。这种特殊的行为实际上是由于孪晶马氏体片晶的变体结构重排：当施加磁场时，磁场倾向于增加两个孪晶之间最佳取向马氏体的体积分数。为了描述和理解这种磁致应变的机制，人们提出了不同的模型（Murray等[1]、James等[2]、Likhachev等[3]和Mullner等[4]）。该模型是为了预测在施加或不施加应力的情况下，5 M或7 M孪晶马氏体单晶中的双轴磁场的影响而编写的。为了简单起见，不考虑退磁场。典型的基本体积是经典地引入不同的微观结构参数，即马氏体带的体积分数，磁化旋转，两个连续磁畴的宽度比。必须承认，这些变量与物理现象有关，例如，180度角的运动。
Abstract. A predictive model of field-induced strain in Ni-Mn-Ga ferromagnetic shape memory alloys is proposed. Theaction of both biaxial magnetic field and mechanical stress on the martensitic rearrangement in a Ni-Mn-Ga single crystal aremodelled. Yield surfaces of starting rearrangement are simulated. They show how applied mechanical stress helps or opposesto the applied magnetic field to make the rearrangement easier or harder. The results are fully compatible with the experimentsof Mullner et al. [8] describing the action of a rotating magnetic field.¨Keywords: Magneto-mechanical coupling, shape memory alloy, model 1. Introduction In the search of new active materials, ferromagnetic shape memory alloys (FSMA) such as Ni-Mn-Gahave a prominent position thanks to their capability to developa strain more important than conventionalactive materials such as piezoelectric and magnetostrictive. Contrary to classical shape memory alloys,theyareabletodevelopthisstrainveryrapidly,underanappliedmagneticfield. Thisparticularbehaviouris in fact due to variant structure rearrangement of twinned martensite platelets: when a magnetic fieldis applied, this one tends to increase the volume fraction of the best oriented martensite between the twotwinned ones. To describe and understand this mechanism of magnetic field-induced-strain, differentmodels were proposed (Murray et al. [1], James et al. [2], Likhachev et al. [3] and Mullner et al. [4]).¨In this paper, the authors propose a magneto-mechanical model based on phenomenology, thermo-dynamics of irreversible processes and changing of scale. This model is written in order to predict theeffect of biaxial magneticfieldin asingle crystalof 5 M or 7 M twinnedmartensite, with appliedstressornot. For sake of simplicity, no demagnetizing field is considered. A Representative Elementary Volumeis classically introduced with different microstructural parameters, i.e. volume fractions of martensiticbands, magnetization rotations, width ratios of two consecutive magnetic domains. It must be noticedthat these variables are linked to physical phenomenon, for example, the movements of 180