Effect of rare earth Dy addition on microstructure and martensitic transformation of polycrystalline Ni50Mn29Ga21−xDyx ferromagnetic shape memory alloys

✍ Scribed by L. Gao; Z.Y. Gao; W. Cai; L.C. Zhao

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 470 KB
• Volume: 438-440
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.02.190

✦ Synopsis

The effects of rare earth Dy addition on microstructure and martensitic transformation of polycrystalline Ni 50 Mn 29 Ga 21-x Dy x (numbers indicate at.%) shape memory alloys were investigated by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry and X-ray diffraction. The results show that the microstructure of Ni-Mn-Ga-Dy alloys consists of the matrix and Dy-rich phase. Small amounts of the Dy-rich phase with 0.1 at.% Dy disperse homogeneously in the matrix. With the increase of the Dy content, the Dy-rich phase becomes larger and trends to distribute along the grain boundaries. The one-step martensitic transformation is observed in Ni 50 Mn 29 Ga 21-x Dy x alloys. With increasing Dy content, the martensitic transformation temperatures of Ni 50 Mn 29 Ga 21-x Dy x alloys increase remarkably, whereas the martensite structure of the Dy-containing alloys appears to be unchanged exhibiting seven-layered martensite structures at room temperature.