铁磁形状记忆合金Co50Ni20Ga30-xSix的结构及物性研究

用Si元素替代CoNiGa合金中的Ga元素后，研究了材料的结构、马氏体相变及其磁性的变化.结果发现，当Si原子的含量在0—10％范围内，材料能够形成体心立方结构，并且具有很好的热弹性马氏体相变行为.进一步研究指出，简单的从掺杂元素的原子半径大小来判断其对奥氏体稳定性的影响是不够的，必须从考虑掺杂原子与基本元素原子半径之间的比例来考虑这一问题.同时还发现Curie温度和饱和磁化强度随着Si含量的上升而有所降低，但是其马氏体的各向异性随着Si含量的增加而增强，这一点对于在合金中获得大磁感生应变具有指导意义. 关键词： 铁磁形状记忆合金 马氏体相变 CoNiGaSi合金

Structure and properties of the ferromagnetic shape-memory alloy Co_(50)Ni_(20)Ga_(30-x)Si_x

The structure, martensitic transformation and magnetism have been studied in the CoNiGa alloys after certain Ga substrated by Si. From the experimental results,we found that the alloy can form pure body-centered cubic structure accompanied by good thermal martensitic transformation when the atom ratio of Si lies in the range 0-10% . It can be concluded from further analysis that it is not only the radius of the doped atom but also the radius ratio of the doped atom and the host atom that affect the stability of the austenite. At the same time, it can be found that the Curie temperature and the saturated magnetization decrease with increasing Si. But the anisotropy of the martensite increases with the increasing Si, which is of significance for obtaining large magnetically-induced-strain.