Amorphization and microstructural evolution in multicomponent (FeCoNi)70Zr10B20 alloy system by mechanical alloying

High energy ball milling of a mixture of elemental and prealloyed powder for 18–27 h has led to an amorphous structure in the multicomponent (Fe1−x−yCoyNix)70Zr10B20 (x=0.1–0.4, y=0, 0.1, 0.3) alloy system. Initially, the starting powder material with mixed crystalline phases transformed into an almost single nanocrystalline supersaturated α-Fe phase after milling for 6 h. Subsequently, the milled powders became less crystalline and more amorphous with further increase in milling time. Co-free (Fe1−xNix)70Zr10B20 (x=0.1, 0.2, 0.4) alloys and the Co-containing (Fe0.6Co0.1Ni0.3)70Zr10B20 alloy tend to readily transform to amorphous structure after milling for 18 h. But Co-free (Fe1−xNix)70Zr10B20 (x=0.3) alloy produced a mixture of nanocrystalline boron-rich phase and amorphous phase after milling for 18 h. However, Co-containing (Fe0.6Co0.3Ni0.1)70Zr10B20 and (Fe0.8Co0.1Ni0.1)70Zr10B20 alloys with a low Ni/Co ratio failed to achieve amorphization even after 27 h. For all milled amorphous alloy powders, the glass transition temperatures, the onset crystallization temperatures lie in 544–577 and 579–619 K range, respectively. The supercooled liquid regions varied from 35 to 42 K, and the crystallization enthalpies varied from 3.2 to 6.9 kJ mol−1 with a change in Ni/Fe ratio.