Martensitic and magnetic transformation behaviours in Mn<sub>50</sub>Ni<sub>42−x</sub>Sn<sub>8</sub>Co<sub>x</sub> polycrystalline alloys
Wu, Zhigang; Liu, Zhuhong; Yang, Hong; Liu, Yinong; Wu, Guangheng; Wu, Zhigang; School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, WA 6009, Australia; Liu, Zhuhong; Department of Physics, University of Science and Technology Beijing, Beijing 100083, People's Republic of China; Yang, Hong; School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, WA 6009, Australia; Liu, Yinong; School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, WA 6009, Australia; Wu, Guangheng; Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100080, People's Republic of China
Журнал:
Journal of Physics D: Applied Physics
Дата:
2011-09-28
Аннотация:
This study investigated the effect of Co substitution for Ni in Mn<sub>50</sub>Ni<sub>42</sub>Sn<sub>8</sub> alloy with the aim of increasing the magnetic driving force for inducing its martensitic transformation. The martensitic transformation temperatures, enthalpy and entropy changes were found to decrease progressively with increasing Co content, while the transformation hysteresis increased. Co substitution for Ni also significantly increased the magnetization of the austenite, but with negligible effect on that of the martensite. A large magnetization difference 109 emu g<sup>−1</sup> was achieved across the transformation in a Mn<sub>50</sub>Ni<sub>34</sub>Sn<sub>8</sub>Co<sub>8</sub> alloy. The large magnetization difference between the two phases provides enhanced thermodynamic driving force for the transformation. Consequently, the martensitic transformation was induced by the application of a magnetic field in Mn<sub>50</sub>Ni<sub>36</sub>Sn<sub>8</sub>Co<sub>6</sub> and Mn<sub>50</sub>Ni<sub>34</sub>Sn<sub>8</sub>Co<sub>8</sub> alloys. The effect of Co substitution for Ni on the magnetic interaction among the constituents for the austenite and martensite was clarified in this study, which provides a guide for alloy design for magnetoactuation applications.
558.9Кб