Zr-Al-Ni-Cu大块非晶合金的变温晶化行为研究

Crystallization of Zr-Al-Ni-Cu Bulk Amorphous Alloy during Continuous Heating

研究了Zr-Al-Ni-Cu大块非晶合金在连续升温过程中的晶化行为。结果表明,随升温速度的加快,特征温度Tg,Tx,Tp均向高温区移动,晶化热焓增加,过冷温度区间扩大,并且峰值温度Tp对应的晶化体积分数减少。利用Kissinger曲线和Doyle曲线法计算合金的变温晶化激活能E,结果表明,晶化激活能随晶化过程的进行,其值先增加后降低,并且在晶化即将结束时,晶化激活能急剧降低。采用Kissinger曲线计算晶化激活能,由于特征温度在不同的加热速度下对应的晶化体积分数发生变化,从而导致了激活能计算值的偏大。

The crystallization behavior of Zr-Al-Ni-Cu bulk amorphous alloy during continuous heating is investigated. The results show that with increasing of heating rates, all the specific temperatures (T(g), T(x), and T(p)) shift to the high temperature region, and the crystallization enthalpy and the enlarged supercooled liquid region increase, while the crystallized volume fraction corresponding to the peak temperature T(p) decreases. Using Kissinger and Doyle plots, the activation crystallization energy can be evaluated. During continuous heating, the activation energy increases with increasing of the crystallized volume fraction at the early stage of crystallization, then decreases slightly and finally drops sharply. The value of activation energy obtained from Kissinger plots is a bit larger than that obtained from Doyle plots due to the change of the crystallized volume fraction at the specific temperature for different heating rates.