材料期刊网

预退火处理对非晶Cu-Ti合金晶化过程动力学的影响

苗卫方 , 王景唐 , 李淑苓

金属学报

对非晶Cu_(40)Ti_(60)合金引入一种预退火处理工艺,利用DSC研究了急冷态及预退火处理样品的晶化过程动力学,发现预退火处理使非晶合金的晶化温度、晶化激活能和Avrami指数值下降。由实验结果和理论分析得到了非晶Cu_(40)Ti_(60)合金的形核激活能和长大激活能。

关键词: 非晶志合金 , crystallization temperature , activation energy , preannealing , Avrami exponent

Effects of Nb Alloying on Nano-Crystallization Kinetics of Fe_55-xCr₁₈Mo₇B₁₆C₄Nb_x(x=0, 3) Bulk Amorphous Alloys

S. Ahmadi

材料科学技术（英文）

Crystallization kinetics of Fe_55-xCr₁₈Mo₇B₁₆C₄Nb_x(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/min) and kinetic models. Two-step crystallization behavior was observed when Fe₅₅Cr₁₈Mo₇B₁₆C₄ and Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ bulk amorphous alloys were annealed, where Fe₃₆Cr₁₂Mo₁₀ 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 Fe₃₆Cr₁₂Mo₁₀ phase was measured to be 543 kJ/mol in Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ alloy and 375 kJ/mol for Fe₅₅Cr₁₈Mo₇B₁₆C₄ alloy according to Kissinger-Starink model. Moreover, a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe₃₆Cr₁₂Mo₁₀ phase during annealing of  Fe₅₅Cr₁₈Mo₇B₁₆C₄ alloy. TEM (transmission electron microscopy) observations reveal that crystalline Fe₃₆Cr₁₂Mo₁₀ phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词: Avrami exponent

Effects of Nb Alloying on Nano-Crystallization Kinetics of Fe_55-xCr₁₈Mo₇B₁₆C₄Nb_x(x=0, 3) Bulk Amorphous Alloys

S. Ahmadi

材料科学技术（英文）

Crystallization kinetics of Fe_55-xCr₁₈Mo₇B₁₆C₄Nb_x(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/min) and kinetic models. Two-step crystallization behavior was observed when Fe₅₅Cr₁₈Mo₇B₁₆C₄ and Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ bulk amorphous alloys were annealed, where Fe₃₆Cr₁₂Mo₁₀ 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 Fe₃₆Cr₁₂Mo₁₀ phase was measured to be 543 kJ/mol in Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ alloy and 375 kJ/mol for Fe₅₅Cr₁₈Mo₇B₁₆C₄ alloy according to Kissinger-Starink model. Moreover, a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in Fe₅₂Cr₁₈Mo₇B₁₆C₄Nb₃ alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe₃₆Cr₁₂Mo₁₀ phase during annealing of  Fe₅₅Cr₁₈Mo₇B₁₆C₄ alloy. TEM (transmission electron microscopy) observations reveal that crystalline Fe₃₆Cr₁₂Mo₁₀ phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词: Avrami exponent

EFFECT OF PRE-ANNEALING ON CRYSTALLIZATION KINETICS OF Cu-Ti GLASS

MIAO Weifang WANG Jingtang LI Shuling Institute of Metal Research , Academia Sinica , Shenyang , China

金属学报(英文版)

The crystallization kinetics of the Cu_(40)Ti_(60) glasses,either as-quenched or pre-annealed,has been studied by differential scanning calorimetry.The crystallization temperature,activation energy for crystallization and Avrami exponent were found to be lowered by the pre-an- nealing.Both activation energies of nucleation and growth of the amorphous CuaoTi_(60) are ob- tained on the basis of experimental results and theoretical analysis.

关键词: metallic glass , null , null , null

非晶软磁合金Co_(65)Fe_4Ni_2Si_(15)B_(14)的纳米晶化动力学研究

赵仲恺 , 周海涛 , 蒋永锋 , 李庆波 , 刘志超 , 温盛发

材料导报

采用差示扫描量热分析(DSC)和X射线衍射技术(XRD)研究了非晶态合金Co_(65)Fe_4Ni_2Si_(15)B_(14)的非等温晶化动力学.结果表明,初始晶化的晶化峰值温度T_p与升温速率β呈线性关系:T_p=11.49lnβ+795.43.采用Kissinger和Doyle-Ozawa方法计算了表观晶化激活能E_a,分别为471.68kJ/mol和461.50kJ/mol.进一步研究发现,该非晶合金的晶化为多阶段的连续形核直至饱和的过程;当进入稳定晶化阶段时,剩余非晶的局域晶化激活能逐渐下降,非晶基体的热稳定性降低,这是由B原子的高温扩散导致的.同时,局域Avrami指数n(α)也反映了不同晶化阶段的形核长大机制.

关键词: Co_(65)Fe_4Ni_2Si_(15)B_(14) , 非等温 , 晶化动力学 , 晶化激活能 , Avrami指数

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

材料科学技术（英文）

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