中频磁脉冲处理Fe_(52)Co_(34)Hf_7B_6Cu_1非晶合金的正电子湮没研究

Investigation of positron annihilation in Fe_(52)Co_(34)Hf_7B_6Cu_1 amorphous alloy treated by intermediate frequency magnetic pulse

对熔体急冷法制备的非晶合金Fe_(52)Co_(34)Hf_7B_6Cu_1进行了不同频率的中频磁脉冲处理,用透射电子显微镜、穆斯堡尔谱、正电子湮没寿命谱等方法研究了处理前后试样的微观结构及结构缺陷变化.结果表明,经中频磁脉冲处理后,样品发生了部分纳米晶化,晶化量随磁脉冲频率增加而增加,当磁脉冲频率为2000 Hz时,晶化量达33.1%;在淬态非晶样品中,正电子在类单空位中的湮没寿命τ_1为150.5 ps,强度I_1为77.7%,在微孔洞中的湮没寿命τ_2为349.7 ps,强度I_2为22-3%;随磁脉冲频率的增加,τ_1,τ_2值呈现减小的变化趋势,与淬态非晶相比,I_1有所增加,I_2下降,τ_1,τ_2的平均值(?)大幅降低.

The effect of intermediate frequency magnetic pulse treatments on Fe52Co34HfTB6Cu1 amorphous alloy prepared by melt-spun technique is investigated. The microstructure and structural defects of the treated specimens are investigated by TEM, Mossbauer spectroscopy and position annihilation lifetime spectra. The results show that the treated specimens by intermediate frequency magnetic pulse are partially crystallized, the content of the crystallization phase increases with the increase of the magnetic pulse frequency, and the crystalline volume fraction is 33.1% at a frequency of 2000 Hz. For the as-quenched amorphous alloy, the annihilation lifetime T1 is 150.5 ps in the monovacancy-like free volume, and the relative intensity 11 is 77.7%. The annihilation lifetime t2 is 349.7 ps in the microvoid, and the relative intensity j2 is 22.3%. With the increase of the magnetic pulse frequency, the values of t1 and T2 of the treated specimens decrease, I1 increases, I2 and I2 decrease compared with the as-quenched amorphous alloy.