Influence of Al on glass forming ability and nanocrystallization behavior of cast-iron based bulk amorphous alloy

摘要

Cast-iron (CI) based bulk amorphous alloy with compositions of Fe_(75.5-x)C_(6.0)Si_(3.3)B_(5.5)P_(8.7)Cu_(1.0)Al_x (x = 0, 1 at.%) was synthesized by Cu mold casting. As indicated by increased critical diameters (d_(max)) for the amorphization, the substitution of Al enhanced the glass-forming ability of the alloy. However, the onset temperature of crystallization (T_x) and the range of supercooled liquid region (ΔT_x) of the alloy decreased upon Al addition from 500 ℃ and 28 ℃ to 475 ℃ and 25 ℃, respectively. It was revealed that the decreased thermal stability of the amorphous phase is related to the enhanced crystallization tendency to form primary α-Fe phase. Upon the nanocrystallization of primary α-Fe phase the Al-added alloy shows enlarged M-s of 176 emu g~(-1), still keeping a reasonable small H_c value of 0.086 Oe. The present study revealed that the minor Al addition enhances not only the glass-forming ability, but also the nanocrystallization behavior of the CI based bulk amorphous alloy.