High-energy mechanical milling-induced crystallization in Fe32Ni52Zr3B13

Amorphous Fe32Ni52Zr3B13, prepared by rapid solidification, undergoes crystallization during high-energy mechanical milling. The resulting structure consists of face-centered cubic (fcc) FeNi and Zr3Ni20B6 nanocrystallites. Structural evolution and defect analysis of as-solidified Fe32Ni52Zr3B13 ribbons with different milling times is investigated. From the differential thermal analysis (DTA) curve of amorphous ribbons, exothermic peaks were observed at 415 °C and 475 °C corresponding to the crystallization of fcc Zr3Ni20B6 phase and fcc FeNi phase, respectively. However, high-energy mechanical milling induces the formation of FeNi within the first 2 h of mechanical milling. Further milling induces the crystallization of Zr3Ni20B6. Doppler broadening positron annihilation spectroscopy (DBPAS) was used to investigate vacancy-type defects. The milling-induced crystallization appears to be related to enhanced vacancy-type defect concentrations allowing growth of pre-existing Fe(Ni) nuclei. The milling and enhanced vacancy concentration also de-stabilizes the glass, leading to decreased crystallization temperatures for both phases, and ultimately eliminating the glass transition altogether.