Ni45Mn44-xFexSn11合金条带马氏体相变研究
时间:2018-05-10 21:32 来源:毕业论文 作者:毕业论文 点击:次
| 摘要Ni-Mn-Sn系列合金存在磁诱导马氏体转变，其磁性变化与其内部晶格关系存在密切联系。本文所研究的主要工作包括完成Ni45Mn44-xFexSn11（x=1、2、4、6）条带样品成分的设计、制备，对Ni45Mn44-xFexSn11合金的XRD、DSC、VSM测试和分析等。 研究表明，随着Fe元素的增加，在Fe含量达到一定量时，在（220）晶面附近有新的衍射峰出现，即合金中有第二相出现。在衍射峰中，条带出现（111）、（311）、（331）超晶格峰，证明了条带不是高度有序的L21结构，而是相对有序度较低的B2结构。 通过DSC分析合金的相变，表明随着Fe掺杂量的增加，相变温度Mp先增加后趋于平缓、而Ap的变化趋势是先增加后减小，最后再增加。这是由于Fe原子的掺入增加了电子浓度，使相变温度升高，而后来平缓下来是因为其他因素，例如晶格常数的改变。 分析得到马氏体相变开始温度Ms，结束温度Mf，逆马氏体开始温度As，逆马氏体相变结束温度Af的变化趋势都是增加的， 而随着Fe原子的掺入，我们发现了条带的磁性呈现出先减小后增大的趋势。 研究表明，Fe的掺入对NiMnSn合金的居里温度有很大的影响，但是，随着Fe含量变化，居里温度变化变得不明显了，我们得到的结论是，Ni45Mn44-xFexSn11合金中，居里温度的变化只与元素种类有关，与元素的含量没有关系。22684 关键词 磁控形状记忆合金 Ni-Mn-Sn 马氏体相变 X射线衍射 甩带 毕业设计说明书（论文）外文摘要 Title Martensitic transformation of Ni45Mn44-xFexSn11 alloy strip Abstract Ni-Mn-Sn ferromagnetic shape memory alloys have the martensite transformation induced by the magnetism. There is a close relationship between the magnetic variation and its internal lattice. The main work in this paper includes: design the nominal composition of Ni45Mn44-xFexSn11(x=1,2,4,6) and finish the preparation of alloys, investigate the properties of the alloys by XRD/DSC/VSM. The research shows that, with the increase of the Fe content, a new diffraction peak appears near the (220) crystal surface, which means the presence of the second phase alloy. In these diffraction peaks, we can see the peak of (111), (311), (331) which are superlattice peaks. It indicates that the ribbons are not highly ordered L21 structure, but the relatively lower ordered B2 structure. Through the analysis of alloy phase transformation by DSC, we can see that with the increase of the Fe content, Mp increases first, and then becomes smooth. This is due to the doping of Fe atoms increases the electron concentration, the phase transition temperature get higher, and then the temperature slowdown, which is because some other factors, such as the change of the lattice constant. In our analysis, the trend of Martensitic transformation start temperature Ms, the end temperature Mf, the reverse martensitic start temperature As, the reverse martensitic transformation finish temperature Af also increase, with the doping of Fe atoms. We found alloy strip magnetic decreased firstly and then increased. The research shows that, the doping of Fe atoms have important influence on the Curie temperature of NiMnSn alloys, but, as the change of Fe content, the change of Curie temperature become indistinct, we come to the conclusion that in Ni45Mn44-xFexSn11 alloys, The variation of Curie temperature is only related with the element type, which has nothing to do with the content of Fe. Keywords：magnetic shape memory alloys, Ni-Mn-Sn, martensitic phase transition, XRD, melt-spun (责任编辑：qin) |