原子空位对定向凝固Fe-Ga合金磁致伸缩性能的影响  

Magnetostrictions of Directionally Solidified Fe-Ga Alloys with Atomic Vacancies

作　　者：李纪恒[1] 高学绪[1] 朱洁[1] 包小倩[1] 张茂才[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《稀有金属》2017年第2期155-162,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51271019;51501006);北京市自然科学基金项目(2132052)资助

摘　　要：采用扩展的X射线吸收精细结构谱和正电子寿命湮没谱对定向凝固<110>取向多晶Fe-Ga合金的局域微观结构和空位缺陷及其对磁致伸缩性能的影响进行了研究。结果表明:在有序转变温度700℃附近进行不同工艺热处理,Fe_(83)Ga_(17)合金中的Ga原子与第一近邻原子Fe的键长和有序度不随热处理温度和冷却方式的变化而发生变化,说明了合金结构并没有随温度和冷却方式发生变化,具有很好的热稳定性。但是,不同工艺热处理后,Ga原子配位数发生变化,随着Ga原子配位数的逐渐降低,合金的磁致伸缩性能提高。对<110>取向多晶Fe_(81)Ga_(19)合金不同热处理工艺后样品空位缺陷的分析表明,淬火处理样品中单空位缺陷浓度最高,未热处理的定向凝固态样品次之,炉冷处理样品最低,与合金的磁致伸缩系数变化规律一致。<110>取向多晶Fe_(81)Ga_(19)合金经淬火处理后,在20 MPa预压力下的磁致伸缩性能达到230×10-6。空位会降低空位周边区域的电子密度,从而改变Fe原子周围的物理环境,从而间接影响Fe-Ga合金的磁致伸缩性能。〈110〉 oriented Fe83Ga17 alloy and Fe81Ga19 alloy were prepared by directionally solidification method at growth rate of720 mm·h-1.Theatomic vacancies of directionally solidified Fe-Ga alloy were investigated by X-ray absorption fine structure spectroscopy and positron annihilation technique.It was found that after different heat treatments around temperature of 700 ℃,the bond length between Ga atoms and its first neighbors Fe atoms and the degree of order of Fe83Ga17 alloys did not vary,indicating that the structure had good thermal stability.However,Ga atomic coordination number changed with different heat treatment processes,and the magnetostrictive properties of the alloy were improved with the decrease of Ga atomic coordination number.As for the 〈110〉 oriented Fe81Ga19 alloy,the magnetostrictions increased with the concentration of single vacancy defects increasing,and the magnetostrictive properties of 230 × 10^-6was achieved at 20 MPa pre-stress in the quenched sample which had the highest concentration of single vacancy defects.The vacancy defects would reduce the electron density of vacancy peripheral region,thereby changed the physical environment around Fe atoms,and thus indirectly affected the magnetostrictive properties of Fe-Ga alloy.

关 键 词：磁致伸缩 FE-GA合金 原子空位 定向凝固 

分 类 号：TM274[一般工业技术—材料科学与工程]