高Fe含量Fe-B-Si-Hf块体非晶合金的结构-性能关联

Structure-Property Correlation of High Fe-Content Fe-B-Si-Hf Bulk Glassy Alloys

以具有最佳非晶形成能力的新型Fe-B-Si-Hf四元块体非晶合金团簇式成分[Si-B_2Fe_(7.7)Hf_(0.3)]Fe(Fe_(72.5)B_(16.7)Si_(8.3)Hf_(2.5))为基础,通过添加Fe原子获得了[Si-B_2Fe_(7.7)Hf_(0.3)]Fe+Fex(x=0、1.5、2、2.5和3,原子个数)系列高Fe含量的Fe-B-Si-Hf四元合金成分。液态急冷、热分析和磁性测量结果表明,随着Fe原子数量的增加,非晶合金的形成能力逐渐降低,形成棒状块体非晶样品的临界尺寸由x=0时的2.5 mm降低到x=2时的1 mm。非晶样品的玻璃态转变温度、晶化温度和Curie温度随Fe原子数量的增加也整体上表现为降低的趋势。该系列非晶样品软磁性能优异,其中[Si-B_2Fe_(7.7)Hf_(0.3)]Fe+Fe_2(Fe_(76.4)B_(14.3)Si_(7.1)Hf_(2.2))块体非晶合金的饱和磁化强度和矫顽力分别为1.58 T和2.8 A/m。为建立高Fe含量Fe-B-Si-Hf非晶合金的结构-性能关联,构建了{[Si-B_2Fe_(7.7)Hf_(0.3)]+[Fe-Fe_(14)]_(x/15)}Fe非晶合金的"双团簇"微观结构模型。结果表明,源于a-Fe的[Fe-Fe_(14)]团簇的数量在Fe-B-Si-Hf四元非晶合金的性能变化中起决定作用。

Fe-based amorphous alloys are well known for their good magnetic properties. But these alloys were only prepared into ribbon form in early times due to their insufficient glass-forming abilities（GFAs）. After first synthesized of Fe-（Al, Ga）-P-C-B bulk glassy alloy, many Fe-based bulk metallic glasses（BMGs） were synthesized. Compared with amorphous alloy ribbons, the GFA of these alloys was significantly improved, but the saturation magnetization（B s） was less than 1.5 T. To achieve higher B s in Febased amorphous alloys, the Fe content should be maximized and the metalloid and alloying elements contents should be minimized, but it makes glass formation difficult. It is difficult to reveal the effect mechanism of Fe atoms in high Fe-content amorphous alloys, due to the complexity of the amorphous structure. The present work focuses on explores the structure-property correlations of high Fe-content Fe-B-SiHf multi-component glassy alloys with an amorphous structure model. A series of high Fe-content alloys with the composition of [Si-B2Fe7.7Hf0.3]Fe＋Fe x（x=0, 1.5, 2, 2.5 and 3） was produced by adding Fe atoms to the ideal cluster formula, which is based on the composition with the best glass-forming ability of [Si-B2Fe7.7Hf0.3]Fe（Fe72.5B16.7Si8.3Hf2.5） for Fe-B-Si-Hf quaternary alloys. Liquid quench, thermal analysis and magnetic measurement results show that the critical rod size for glassy alloys gradually decreases from 2.5 mm to 1 mm as the number of Fe atoms increases from 0 to 2. The [Si-B2Fe7.7Hf0.3]Fe＋Fe2（Fe76.4B14.3Si7.1Hf2.2） bulk glassy alloy has a high saturation magnetization of 1.58 T and a low coercive force of 2.8 A/m. The decreasing of the glass transition temperature, the thermal stability, the glass-forming ability and the Curie temperature with increasing Fe content in Fe-B-Si-Hf glassy alloys was evaluated using a＂dual-cluster＂（{[Si-B2Fe7.7Hf0.3]＋[Fe-Fe14]x/15}Fe） amorphous structure model. The result shows that the [Fe-Fe14] cluster from the a-Fe phase plays an important role in determining the properties change for this series high Fe-content Fe-B-Si-Hf glassy alloys.