特种烧结及磁性能
( 1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中国科学院 上海硅酸盐研究所 特种材料研究与发展中心，
上海 200050)
摘 要: 研究了放电等离子烧结和高压烧结工艺条件对MA Fe73.5Cu1Nb3Si13.5B9纳米晶粉末的烧结块体合金的组织结构与磁性能的影响。 结果表明： 球磨70 h后， 获得了单相α-Fe纳米晶(约9.5 nm)过饱和固溶体粉末； DSC升温曲线中， 出现4个不同强度的放热峰， 依次发生了纳米晶过饱和固溶体的结构弛豫、 非晶晶化以及过饱和固溶体相析出等过程， 且相析出过程分两个阶段完成； 在p=30 MPa, t=5 min放电等离子烧结(SPS)条件下， 当温度达到1 050 ℃后， 可获得相对密度为98.9%、 主相为α-Fe的纳米晶(100 nm)块体合金， 其中， Bs=1.34 T, Hc=7.34 kA/m， 在p=5.5 GPa, t=5 min条件下， 当Pw=1 150 W后, 可获得相对密度约99.1%、 单相α-Fe纳米晶(21.4 nm)块体合金， 其中， Bs=1.14 T, Hc=8.22 kA/m。
关键字: Fe基合金； 机械合金化； 纳米晶； SPS烧结； 高压烧结； 块体合金； 磁性能
mechanical alloying Fe73.5Cu1Nb3Si13.5B9
nanocrystalline powder
（ 1. School of Materials Science and Engineering,
Central South University, Changsha 410083, China;
2.Special Materials Research and Development Centre,
Shanghai Institute of Ceramics, Chinese Academy of Science,
Shanghai 200050, China）
Abstract: The influence of spark plasma sintering and high-pressure sintering technique on microstructure and magnetic properties of bulk alloys of MA Fe73.5Cu1Nb3Si13.5B9 nanocrystalline powder were investigated. The results show that after milling for 70 h, the single phase α-Fe nanocrystalline supersaturate solid solution powder with average grain size 9.5 nm and bcc structure can be obtained. In DSC heating-up curve of MA powder, four exothermal peaks with different strength appear, which are corresponding to the structure relaxing process of distorted nanocrystalline supersaturate solid solution, crystallization process of trace amorphous phases and phase precipitation of supersaturate solid solution, respectively. The precipitation process of supersaturate solid solution is decided into two stages. Under the SPS sintering conditions at p=30 MPa, t=5 min, when sintering temperature is 1 050 ℃, nanocrystalline (100 nm) bulk alloy with relative density of 99% and main phase of α-Fe can be obtained, the magnetic properties of bulk alloy are: Bs=1.34 T, Hc=7.34 kA/m. Under the high-pressure sintering conditions of p=5.5 GPa, t=5 min, when Pw=1 150 W, single phase α-Fe nanocrystalline (21.4 nm) bulk alloy with relative density of 99.1% can be obtained, the magnetic properties of which are: Bs=1.14 T, Hc=8.22 kA/m.
Key words: Fe-based alloy; mechanical alloying; nanocrystalline; SPS sintering; high-pressure sintering; bulk alloy; magnetic properties
