FeCoNbSiBCu大块非晶合金的热稳定性与晶化过程研究

Thermal Stability and Crystallization Process of FeCoNbSiBCu Bulk Metallic Glasses

用差示扫描量热分析和原位高温X射线衍射研究了(Fe36Co36Nb4Si4.8B19.2)100-xCux(x=0,0.5,0.6,0.7)大块非晶合金的热稳定性及其晶化过程。结果表明,微量Cu显著改变了Fe36Co36Nb4Si4.8B19.2大块非晶合金的晶化过程,无铜合金表现出单一尖锐晶化峰,而含铜量原子分数为0.5%,0.6%和0.7%的晶化过程分为四个阶段,Cu的加入提高了非晶合金纳米析出相的热稳定性。原位X射线衍射研究表明,FeCoNbSiBCu大块非晶合金初始晶化相为bcc-FeCo并于930K转变为bcc-Co7Fe3相。Cu添加后bcc-Co7Fe3的晶化表观激活能由460.41kJ/mol升高至545.69kJ/mol。用谢乐公式计算样品在840K保温17.5min的平均晶粒尺寸为22.3nm。

Thermal stability and crystallization process of （Fe36Co36Nb4 Si4.8 B19.2 ） 100-x Cux （x = 0, 0.5, 0.6, 0.7） Bulk Metallic Glasses （BMGs） were studied by Differential Scanning Calorimetry （DSC） and in situ high temperature X Ray Diffraction （XRD）. The minor addition of Cu significantly changes the crystallization process of the Fe36Co36 Nb4 Si4. 8B19.2 BMG. The Cu free alloy shows single sharp exothermic peak during crystallization, whereas the Cu containing alloys exhibit four broad crystallization peaks. In situ high temperature X ray diffraction study shows that the bcc-FeCo precipitated from the amorphous precursor and transformed to bcc-Co7Fe3 at 930 K in the Cu containing alloys. The apparent crystallization active energy of bcc-Co7Fe3 is increased from 460.41kJ/mol to 545.69kJ/mol after Cu addition. The average grain size of the sample annealed at 840K for 17.5 minutes is 22.3nm calculated by Scherrer method.