摘要
本文主要研究了Cu取代和退火等因素对全过渡族Mn_(50)Ni_(32–x)CuxCo_(8)Ti_(10)(x=1, 2)合金条带马氏体相变行为和磁热性能的影响.研究发现, Cu取代后,合金马氏体相变温度往低温方向移动,且对Cu含量非常敏感;同时奥氏体铁磁性增强,导致相变前后磁化强度突变增大;发生明显的磁场驱动变磁性马氏体相变;磁熵变随着Cu含量的增加而逐渐增大,尤其是有效制冷能力相对于Cu取代前样品成倍增大.本文以x=1样品研究了退火对马氏体相变的影响,退火后,合金马氏体相变变得缓慢,奥氏体铁磁性减弱,相变前后磁化强度突变减小,磁场驱动变磁性变弱,由此导致磁熵变大幅度减小,但由于制冷温区成倍增大,致使有效制冷能力几乎不减小.本文从过渡元素取代导致3d电子之间相互作用的改变和退火导致γ相的析出分别讨论了Cu取代和退火影响合金马氏体相变的物理机制.
The effects of Cu substitution and annealing on the martensitic transformation behavior and magnetocaloric properties in all-d-metal Mn_(50)Ni_(32–x)CuxCo_(8)Ti_(10)(x=1,2) alloy ribbons have been mainly investigated. After the substitution, it is observed that the martensitic transformation temperature of the alloys, which was extremely sensitive to the Cu content,was reduced. Moreover, the ferromagnetism of austenite increased, increasing the magnetization difference across the martensitic transformation. The magnetic-field-induced metamagnetic martensitic transformation also occurred. The magnetic entropy change gradually increased, and the effective refrigeration capacity increased by more than twice than that of the Cu-free substitution. Moreover, the sample with x=1 was utilized as the research object to study the effect of annealing on the martensitic transformation. After annealing, the martensitic transformation became slow and the austenite ferromagnetism decreased. The change in the magnetization across the phase transition was also reduced. The magnetic-field-induced metamagnetic martensitic transformation was also weakened. Consequently, the magnetic entropy change was greatly reduced. However, the effective refrigeration capacity did not reduce significantly because the refrigeration temperature interval increased largely. In this paper, the physical mechanisms of the effects of Cu substitution and annealing on the martensitic transformation were discussed from the change in the d-d interaction and the precipitation in the γ-phase, respectively.
作者
张玉希
刘小川
余广
郑先明
万铎建
罗小华
陈长材
马胜灿
ZHANG YuXi;LIU XiaoChuan;YU Guang;ZHENG XianMing;WAN DuoJian;LUO XiaoHua;CHEN ChangCai;MA ShengCan(Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices/Institute for Rare Earth Magnetic Materials and Devices(IREMMD),College of Rare Earths,Jiangxi University of Science and Technology,Ganzhou 341000,China;Faculty of Materials Metallurgy and Chemistry,School of Materials Science and Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China)
出处
《中国科学：物理学、力学、天文学》
CSCD
北大核心
2021年第6期107-115,共9页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(编号:52061014)
江西省自然科学基金重点项目(编号:20192ACB20004)
南京大学固体微结构物理国家重点实验室开放课题(编号:M32027)资助。
