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Fe-based bulk metallic glasses (BMGs) with high glass forming ability (GFA) and excellent mechanical properties were synthesized in FeNi-Mo-P-C-B alloy system by copper mold casting. Results show that the glass forming ability of Fe 74Àx Ni x Mo 6 P 10 C 7:5 B 2:5 alloys increases first and then decreases as Ni content, x, increases from 0 to 11.1 at%, with its climax being reached at x is between 3.7 and 5.0. Analyses indicate that either ÁT x and ÁH endo or T rg and can not illustrate the GFA of obtained alloys solely. With increasing Ni element in Fe 74Àx Ni x Mo 6 P 10 C 7:5 B 2:5 alloys, the yield strength and Vicker's mircrohardness decline, while the plasticity increases, which implies that enhancing plasticity by adjusting the composition of alloys is followed with the loss of some strength. Serrated flow characteristics on the compressive stress-strain curves is observed for Fe 74Àx Ni x Mo 6 P 10 C 7:5 B 2:5 as x ¼ 11:1 at%, which is considered to relate to its lowest glass transition temperature. These mechanical properties of BMGs are illustrated with bonding nature between the constituent elements.

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Formation of icosahedral clusters in Ni 66.7 Zr 33.3 alloy during rapid solidification is studied with molecular dynamics simulations. It is found that the growth rate of the smallest icosahedral cluster (Ih13) in Ni 66.7 Zr 33.3 alloy reaches its maximum at glass transition temperature region. The Ih13 in Ni 66.7 Zr 33.3 alloy contain the retained from the higher temperatures and the new grown, which reach its maximum at about 900K as well as the new grown vertex atoms of Ih13. The ratio of new grown center atoms to the new grown vertex atoms increases with decreasing temperatures, which implies that the new Ih13 form beside original Ih13 and the icosahedral clusters coalesce to the larger ones during solidification. The stabilities of center atoms and vertex atoms of Ih13 increase with decreasing temperatures, and the stability of the center atoms becomes larger than that of vertex atoms blow 900K because of its rapid increase at glass transition temperatures. The results show that the evolutions of atomic arrangement during cooling change abruptly at glass transition region.

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