大块非晶临界冷却速率的非等温转变计算模型

在非等温转变理论以及非稳态形核理论基础上提出了计算大块非晶合金连续冷却转变曲线和 临界冷却速率的新模型,以用于评估合金的非晶形成能力. 依据此模型对Zr基和Pd基8种合金 进行了计算，计算结果与实验值符合较好. 计算结果表明，影响临界冷却速率的主要因素为 黏度、临界形核功和临界结晶分数. 随着黏度增大，临界冷却速率降低；随临界形核功增大 ，临界冷却速率急剧降低；随临界结晶分数增大，临界冷却速率起初降低较快，达到一定程 度后下降速率趋于缓慢. 关键词： 临界冷却速率 非晶形成能力 大块非晶 连续冷却转变曲线

A new model for calculating the critical cooling rate of bulk metallic glass under non-isothermal condition

Based on the non-isothermal transformation theory and non-steady state nucleatio n theory, a new method for calculating the continuous cooling transformation cur ve and the critical cooling rate of bulk metallic glass alloys is put forward in this paper. The continuous cooling transformation curves of Zr- and Pd-based al loys are calculated and the results are in good agreement with the experimental values. It is suggested that the method can be used to evaluate glass forming ab ility of alloy systems more effectively. In addition, the calculation results sh ow that the main factors effecting the critical cooling rate are the viscosity o f melt, nucleation barrier and critical volume fraction of the crystal, the crit ical cooling rate is reduced with the increase of the viscosity, nucleation barr ier and critical volume fraction of crystal.