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通过磁悬浮熔炼-水冷铜模吸铸法制备了Cu46Zr44Al5Nb5块体非晶合金,并研究其变温晶化行为和等温晶化行为,运用Kissinger法和FWO法分别计算出各特征激活能和阶段激活能,考察了不同加热速度下晶化体积分数和晶化温度、晶化激活能的关系,并绘制了TTT曲线并计算非晶形成的临界冷却速率。结果表明,运用Kissinger法得到玻璃转变激活能E g为231.96 kJ·mol-1、晶化初始激活能E x为351.39kJ·mol-1、晶化峰的激活能E p为401.36 kJ·mol-1,Cu46Zr44Al5Nb5BMG具有良好的热稳定性,由TTT曲线计算非晶形成的临界冷却速率约为3.985 K·s-1。晶化类型主要为扩散控制的共晶型转变,随着晶化量的增大,阶段激活能呈减小的趋势。初始晶化阶段的晶化温度较高,主要是形核和微小晶粒的长大,需要克服较大的能量势垒,而随着温度的降低,晶粒的不断形成,晶化过程演变为主要以形核为主,所需要克服的能量势垒相应减小。在T x+100℃等温晶化退火,析出Cu10Zr7和AlCu2Zr共晶相,随着保温时间的延长,析出相的尺寸和体积分数逐渐增加。
The Cu46Zr44Al5Nb5 bulk amorphous alloy was prepared by magnetic levitation-water-cooled copper die-casting method and its temperature-programmed crystallization behavior and isothermal crystallization behavior were studied. Kissinger method and FWO method were used to calculate the activation energy and phase activation energy respectively. The relationship between the crystallization volume fraction, crystallization temperature and crystallization activation energy at different heating rates was investigated. The TTT curve was plotted and the critical cooling rate of amorphous formation was calculated. The results showed that the activation energy E g of Kissinger method was 231.96 kJ · mol-1, the initial activation energy E x was 351.39 kJ · mol-1 and the activation energy E p was 401.36 kJ · mol- 1, Cu46Zr44Al5Nb5BMG has good thermal stability. The critical cooling rate calculated by TTT curve is about 3.985 K · s-1. The type of crystallization is dominated by diffusion-controlled eutectic transformation. As the amount of crystallization increases, the phase activation tends to decrease. The crystallization temperature in the initial crystallization stage is high, mainly the nucleation and the growth of tiny grains, which need to overcome the larger energy barrier. As the temperature decreases, the continuous formation of grains, the crystallization process evolves The main nuclear-based, the need to overcome the corresponding reduction of the energy barrier. The isothermal crystallization annealing at T x + 100 ℃ precipitates Cu 10 Zr 7 and Al Cu 2 Zr eutectic phases. With the increase of holding time, the size and volume fraction of precipitated phase increase gradually.