Fe_(74)Al_4Ga_2P_(12)B_4Si_4块体非晶合金的纳米晶化及软磁性能研究

Nanocrystallization and Soft Magnetic Properties of Fe_(74)Al_4Ga_2P_(12)B_4Si_4 Bulk Metallic Glass

采用铜模铸造法制备了厚2mm的Fe74Al4Ga2P12B4Si4块体非晶合金。利用X射线衍射(XRD)、差热分析(DSC)和振动样品磁强计(VSM)研究了其晶化行为和软磁性能。结果表明,非晶合金的玻璃转变温度Tg为457.35℃,晶化开始温度Tx为497.65℃。合金的过冷液相区宽度ΔTx达到40.30℃,表明合金具有较大的玻璃形成能力。Fe74Al4Ga2P12B4Si4合金的晶化是二级晶化过程。经520℃等温退火后析出α-Fe相,其晶粒尺寸为15.9nm;而经550℃等温退火后析出α-Fe相及微量的Al0.3Si0.7Fe3和Fe3B相,其中α-Fe相的晶粒尺寸为17.4nm。非晶合金的饱和磁化强度为108.816emu/g、矫顽力Hc为574.97Oe;经520℃等温退火后,纳米晶合金的饱和磁化强度为106.875emu/g、矫顽力Hc为94.16Oe。退火实验结果表明,纳米晶化对材料的饱和磁化强度没有显著影响,但会显著降低材料的矫顽力。

Fe74 Al4 Ga2 P12 B4 Si4 bulk metallic glass with about 2mm thickness is prepared by copper mold casting method. The crystallization behavior and soft magnetic properties of Fe74 Al4 Ga2 P12 B4 Si4 bulk metallic glass are studied by XRD, DSC and VSM. The bulk metallic glass shows a large glass-forming ability with a glass transition temperature Tg of 457. 35℃, a crystallization temperature Tx of 497.65℃ and a width of supercooled liquid region ATx of 40. 30℃. Annealing at 520℃ for 15main results in the formation of bcc α-Fe phase with the grain size of 15. 9nm. While annealing at 550 ℃ for 15min leads to the precipitations of Al0. 3 Si0. 7 Fe3 and Fe3 B phases besides of α-Fe phase with the grain size of 17.4nm. The bulk metallic glass exhibits a saturation magnetization of 108. 816emu/g and a coercivity of 574.97Oe. While the alloy annealed at 520℃ for 15min shows a saturation magnetization of 106. 875emu/g and a coercivity of 94.16Oe. It is shown that the nanocrystallization of Fe74 Al4 Ga2 P12 B4 Si4 bulk metallic glass can reduce its coercivity, though it has no apparent effect on saturation magnetization.