新型纳米晶合金Fe_(69.5)Cu_(0.5)Cr_4V_5Si_(13)B_8退火过程中微结构的Mossbauer研究

Mossbauer Study of the Microstructure During Annealing of New Microcrystalline Fe_(69.5)Cu_(0.5) Cr4 V_5 Si_(13)B_8 Alloy

采用Mssbauer、X-射线衍射(XRD)等实验方法研究了新型纳米晶合金Fe_(69.5)Cu_(0.5)Cr_4V_5Si_(10)B_8退火过程中微结构的变化。实验结果表明,该合金经540℃退火40分钟后能获得优良的综合软磁性能,此时,合金形成双相结构,即具有DO_3型超点阵结构的α-Fe(Si)固溶体超细颗粒和作为品界的富Cr、V、B等元素呈弱铁磁性的非晶相。超细颗粒的尺寸为20nm左右。当退火温度超过600℃后,残余的非晶相就全部晶化。有序相α-Fe(Si)晶粒的颗粒度也明显长大。样品中同时析出Fe_2B和Fe_(1.75)VSi等化合物,磁性能大大恶化。

We have studied in detail the change of the microstructur e of a new Fe69.5Cu0.5Cr4V5Si13B8 alloy during annealing by using Mossbauer spe-ct roscopy and X-ray diffraction. The experimental results show that the specimen annealed at 540 ℃ for 40 rain has superior magnetic properties and consists of two phases: ultrafinc partic\es of DO3-Fe(Si) crystals and a residual amorphous phase probably enriched with Cr,V and B,The amorphous phase is considered as a kind of grain boundaries with weak ferromagnetism, The gra in size of the DO3-Fe(Si) phase is about 20nm. When the annealing temperature is above 600℃ ,the residual amorphous phas -e crystallizes completely. The Fe2B and Fe1. 75VSi compound etc, appear in the specimen. The grain size of an ordered phase α-Fe(Si) increases obvious ly and the magnetic properties greatly deteriorates.