Ni53.2Mn22.6Ga24.2单晶的磁控形状记忆效应和磁控超弹性特性

MAGNETIC-FIELD-CONTROLLED SHAPE MEMORY EFFECT AND SUPERELASTICITY OF N_(i53.2)Mn_(22.6)Ga_(24.2) SINGLE CRYSTAL

证实了Ni_(53.2)Mn_(22.6)Ga_(24.2)单晶发生的两步马氏体相变行为是完全热弹性的.在磁场作用下,该材料的马氏体相变和中间马氏体相变展现出相同的应变特征,且具有磁控双向形状记忆效应.磁场下应力-应变特性的测量结果表明,磁场不但对压应力诱发马氏体相变过程中变体重取向所需应力的大小有影响,而且使原来不可逆的形变成为可逆,这种磁控超弹性特性预示了该合金用作磁控超弹性元器件材料的可能性.

A two-step complete thermoelastic martensitic transformation, martensitic transformation and intermartensitic transformation, in Ni53.2Mn22.6Ga24.2 single crystal was proved. The transformation characteristics of the alloy under the separate and complex actions of temperature, magnetic field and stress were studied. The results show that the martensitic and intermartensitic transformations exhibit the same transition character, and this alloy exhibits a magnetic-field-controlled shape memory effect. Moreover, the stress-strain measurements of the single crystal under the magnetic field indicate that the magnetic field not only has an effect on the stress needed for reorientation of the variants during the martensitic transformation, but also makes the initial irreversible transition become reversible. The magnetically controlled superelastic characteristic of the Ni53.2Mn22.6Ga24.2 single crystal predicts the possibility of utilizing the alloy as magnetically controlled element.