摘要
采用铜模吸铸法制备了直径3 mm的Cu_(40)Zr_(44)Ag_8Al_8大块非晶合金(BMGs),并分别利用X射线衍射仪(XRD)和同步示差扫描量热仪(DSC)对其晶化过程中显微结构的演变及其晶化动力学进行研究。结果显示,该BMGs在晶化过程中依次从非晶基体中析出Al_3Zr和Cu_10Zr_7相。采用Kissinger和Ozawa方法计算的非晶样品第一晶化峰的晶化激活能分别为315.69和312.65 k J/mol,该非晶合金具有很强的热稳定性。此外,该非晶合金晶化过程具有很强的动力学效应,特征温度对升温速率的依赖性遵循Lasocka方程,但其晶化机理函数却无明显的动力学效应,与加热速率无关。采用GM模型对30 K/min加热速率下的DSC实验数据进行拟合,发现其拟合参数由λi=5.2,n=3.4变为λi=2.5,n=4,说明该非晶合金的晶化行为遵循形核率随时间增加而不断增加的初晶型晶化规律。
Copper-mold suction casting was employed for the Cu40Zr44Ti8Al8 bulk metallic glasses（BMGs） preparation. X-ray diffraction（XRD） and differential scanning calorimetry（DSC） were used to analyze the microstructure evolution and crystallization kinetics of the samples. Results show that Al3Zr and Cu10Zr7 precipitate from the amorphous matrix successively. The activation energy of the first crystallization peak calculated by the Kissinger and Ozawa method are 315.69 and 312.65 k J/mol, respectively, so the BMGs are highly thermal stable. Crystallization process of the BMGs shows an obvious kinetic effect. The dependence of the characteristic temperatures on the heating rate follows Lasocka equation. But crystallization mechanism of the BMGs hardly shows any kinetic effect and has nothing to do with heating rate. Parameters fitted by the GM modal under the heating rate of 30 K/min change form λi=5.2, n=3.4 to λi=2.5, n=4, indicating that the BMGs experiences an increasing nucleation and growth rates in the primary crystallization process.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2016年第1期141-144,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51061008)
关键词
晶化动力学
非等温晶化
大块非晶
激活能
晶化机理
crystallization kinetics
non-isothermal crystallization
bulk metallic glasses
activation energy
crystallization mechanism
