摘要
利用差示扫描量热法(DSC)和X射线衍射法(XRD)研究了非晶合金Zr65Al10Ni10Cu15和Zr52.5Al10Ni10Cu15Be12.5的晶化动力学情况。结果表明,在恒速升温情况下,随着升温速率的加快,非晶合金的特征温度Tg、Tx、Tp均向高温区移动,其过冷液相区的宽度也逐渐增加,表明非晶合金的玻璃转变和晶化均具有动力学效应;在等温晶化情况下,利用JMA方程计算出两种合金的Avrami指数和有效激活能,由此得出这两种合金的晶化同为受扩散机制控制的形核率随时间增加而下降的晶化过程;并且非晶合金Zr52.5Al10Ni10Cu15Be12.5的热稳定性要强于Zr65Al10Ni10Cu15,经过分析认为,造成这一现象的主要原因是原子半径较小的Be原子与合金中的其它原子组成紧密的堆垛结构,抑制了合金元素的长程扩散。
Different scanning calorimeter （DSC） and X-ray diffraction （XRD） has been used to investigate crystallization kinetics of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 amorphous alloy.The results showed that the characteristic temperatures （Tg,Tx and Tp） of amorphous alloy shifted to high temperature region and the supercooled liquid region increased as the heating increased with constant rate which indicated that glass transformation ability and crystallization of amorphous alloy had a dynamic effect.The values of Avrami exponent and activation energy have been obtained under isothermal condition by the Johnson-Mehl-Avrami equation,which suggest that crystallization of these two alloys were a similar process in that controlled by volume diffusion and with nucleation rate decreased with time.and the thermal stability of amorphous alloy Zr52.5Al10Ni10Cu15Be12.5 was better than Zr65Al10Ni10Cu15,the main reason was that Be atom with smaller radius formed with other atoms of the alloy to constitute dense atomic configuration, which restrained diffusing of alloy elements.
出处
《中国铸造装备与技术》
CAS
2009年第3期18-21,共4页
China Foundry Machinery & Technology
关键词
大块非晶合金
晶化动力学
激活能
热稳定性
bulk amorphous alloy, crystallization kinetics, activation energy, thermal stability
