Martensitic transformations in some ferrous and non-ferrous alloys under magnetic field and hydrostatic pressure
Martensitic transformations in some ferrous and non-ferrous alloys under magnetic field and hydrostatic pressure
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DOI：
10.1080/01411599908240678
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发表时间：
1999-01-01
影响因子：
1.6
通讯作者：
Endo, S
中科院分区：
文献类型：
--
作者：
Kakeshita, T;Saburi, T;Endo, S
马氏体相变受温度、单轴应力、相变温度、结晶学以及产物马氏体量和形态等外场的广泛影响。因此，要弄清外场对马氏体相变的影响，理解相变的基本问题是非常重要的，如热力学、动力学和相变的起源，这些信息在利用相变的技术应用中自然是有用的。在这种外场中，磁场和静水压力是很重要的，因为母体和马氏体态在磁矩和原子体积上存在着显著的差异。因此，在本文中，我们通过参考本课题组和许多其他研究人员过去和最近的工作，总结了磁场和静水压力对音速黑色金属和有色金属合金马氏体相变的影响。所有铁合金的相变起始温度都随着磁场的增加而升高，但有色金属合金，如Ti-Ni和Cu-Al-Ni形状记忆合金的相变起始温度不受影响。另一方面，在某些铁基合金中，相变起始温度随静水压力的增加而降低，而在铜铝镍合金中则随静水压力的增加而升高。在对Fe-Ni-Co-Ti形状记忆合金的研究中，我们发现在Fe-Ni-Co-Ti形状记忆合金中出现了磁弹性马氏体相变，并且在Fe-Ni合金单晶样品中有几个马氏体片几乎平行于外加磁场的方向生长。我们进一步发现，在磁场作用下，Fe-Ni-Mn合金的等温过程转变为非等温过程，而在静水压力作用下，非等温过程转变为等温过程。基于这些事实，建立了一个现象学理论，它统一了这两个转变过程。
Martensitic transformations are extensively influenced by external fields, such as temperature and uniaxial stress, in transformation temperatures, crystallography and amount and morphology of the product martensites. Therefore, to clarify the effect of external fields on martensitic transformations it is very important to understand the essential problems of the transformation, such as thermodynamics, kinetics and the origin of the transformation, whose information is naturally useful in technological applications using the transformation. Magnetic field and hydrostatic pressure are important in such external fields because there exist some significant differences in magnetic moment and atomic volume between the parent and martensitic states. In the present paper, therefore, we summarize the effects of magnetic field and hydrostatic pressure on martensitic transformations in sonic ferrous and non-ferrous alloys by referring to past and recent works made by our group and many other researchers. The transformation start temperatures of all the ferrous alloys examined increase with increasing magnetic field, but those of non-ferrous alloys, such as Ti-Ni and Cu-Al-Ni shape memory alloys, are not affected. On the other hand, the transformation start temperature decreases with increasing hydrostatic pressure in some ferrous alloys, but increases in Cu-Al-Ni alloys. The magnetic field and hydrostatic pressure dependencies of the martensitic start temperature are in good agreement with those calculated by our proposed equations.During investigations of ferrous Fe-Ni-Co-Ti shape memory alloy, we found that a magnetoelastic martensitic transformation appears and, in addition, several martensite plates grow nearly parallel to the direction of the applied magnetic field in a specimen of Fe-Ni alloy single crystal.We further found that the isothermal process in Fe-Ni-Mn alloy changes to athermal under a magnetic field and the athermal process changes to isothermal under hydrostatic pressure. Based on these facts, a phenomenological theory has been constructed, which unifies the two transformation processes.