Giant magnetostrictive materials are increasingly proposed for smart material applications such as in sensors, actuators, and energy harvesting applications. However, reviewing the literature on this topic, the reader observes a large amount of variability in the reported properties that are typically generated from overall strain or point-value strain measurements obtained with strain gages using the far field estimate to project the internal magnetic field in the specimen. A full-field phase-sensitive thermography method is proposed to correlate the full-field infrared measurements to changes in the microstructure induced by a cyclic magnetic field in a giant magnetostrictive alloy material. The results show the potential of the proposed method in rapidly uncovering the effects of geometry and defects on the magnetostrictive response. The results show responses at the microstructure level from both magnetocaloric and magnetostrictive effects. The effects of the magnetostrictive material’s microstructural spatial variability and the specimen geometry on the localized magnetostrictive response warrant serious considerations but so far have not received significant attention. The method proposed is capable of highlighting magneto-elastic coupling in the composite specimens using the cycle magnetic field.

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全场红外相敏热成像技术用于巨大磁致伸缩材料的微观结构研究

越来越多地提出将巨磁致伸缩材料用于智能材料应用，例如传感器，致动器和能量收集应用。但是，通过阅读有关该主题的文献，读者可以观察到所报告特性的大量变化，这些特性通常是通过使用远场估算来投影内部磁场的应变计获得的总应变或点值应变测量结果产生的标本。提出了一种全场相敏热成像方法，以将全场红外测量结果与巨型磁致伸缩合金材料中由循环磁场引起的微观结构变化相关联。结果表明，该方法在快速揭示几何形状和缺陷对磁致伸缩响应的影响方面具有潜力。结果表明，在微观结构水平上，磁热效应和磁致伸缩效应都产生了响应。磁致伸缩材料的微观结构空间变异性和样品几何形状对局部磁致伸缩响应的影响值得认真考虑，但到目前为止尚未引起足够的重视。所提出的方法能够利用循环磁场突出复合材料样本中的磁弹性耦合。