Effects of Nb Alloying on Nano-Crystallization Kinetics of Fe55-xCr18MoTB16C4Nbx（x=0, 3） Bulk Amorphous Alloys

• 来源期刊: 材料科学技术学报：英文版
• 学科: 工学
• 关键词: 大块非晶合金 晶化动力学 纳米 结晶动力学 透射电子显微镜 动力学模型 Nb 差示扫描量热
• 年，卷（期）: 2011,（8）
• 页码范围: 735-740
• 页数: 6页
• 分类号: TG139.8|TB383
• 语种: 英文

摘要

Crystallization kinetics of Fe55-xCrzsMo7B10C4Nbx（x= 0, 3） bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning; calorimetric （DSC） tests. In practice, crystallization and growth mechanism were evaluated using DSC tests at four different heating rates （10, 20, 30, and 40 K/rain） and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18MOTB16C4 and Fe52Cr18MoTB16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12M010 phase was crystallized in the first step of crystallization. Results show that Fe36Cr12Mo10 and Fe3C phases were crystallized in the structures of the alloys after further annealing： process. Activation energy for the crystallization of Fe36Cr12Mozo phase was measured to be 543 kJ/mol in Fe52Cr18MoTB16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-Starink model. Moreover, a two-dimensiona nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 diffusion controlled growth mechanism with decreasing alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Crz2Mo10 phase during annealing of Fe55Cr18MoTB16C4 alloy. TEM （transmission electron microscopy） observations reveal that crystalline Fe36Cr12M010 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.