Advances in Manufacturing ›› 2014, Vol. 2 ›› Issue (4): 353-357.doi: 10.1007/s40436-014-0093-y

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Crystal structure and formation mechanism of the secondary phase in Heusler Ni-Mn-Sn-Co materials

Jin-Ke Yu 1, Hong-Wei Li1, Qi-Jie Zhai2, Jian-Xun Fu2, Zhi-Ping Luo3, Hong-Xing Zheng1   

  1. 1.Laboratory for Microstructures, Shanghai University,Shanghai 200072, People’s Republic of China 2.Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072, People’s Republic of China 3. Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301, USA
  • Received:2014-04-17 Online:2014-12-25 Published:2014-12-25
  • Contact: e-mail: hxzheng@shu.edu.cn
  • About author:e-mail: hxzheng@shu.edu.cn
  • Supported by:
    The authors gratefully acknowledge the supports from the National Natural Science Foundation of China (Grant Nos. 51201096 and 51474144), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20123108120019), and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

Abstract: In the present work, crystal structure and formation mechanism of the secondary phase in Heusler Ni-Mn-Sn-Co materials were investigated using X-ray diffraction, scanning/transmission electron microscopy and selected-area electron diffraction techniques. Experimental results showed that the secondary phase presented in both Ni44.1Mn35.1Sn10.8Co10 as-cast bulk alloy and melt-spun ribbon, possessing a face-centered cubic (fcc) Ni17Sn3-type structure. The secondary phase in the as-cast bulk alloy was resulted from a eutectic reaction after the formation of a primary dendritic b phase during cooling. However in the melt-spun rapidly solidified ribbon, the secondary phase was largely suppressed as nano-precipitates distributed along the grain boundaries, which was attributed to a divorced eutectic reaction. The secondary phase exhibited partial amorphous state due to high local cooling rate.

Key words: Heusler Ni-Mn-Sn-Co materials , Secondary phase , Melt spinning , Divorced eutectic reaction , Microstructure