采用DSC技术研究了Fe-B合金冷却速率及试样纯度对其非平衡凝固过程的影响,得到了不同实验条件下过冷度和转变分数的演化结果,并从经典形核理论、非等温结晶动力学等方面进行了分析和讨论。实验结果表明,随冷却速率的增加,过冷度逐渐增大,最大可达409K;在同一冷却速率下,熔体的过冷度随试样纯度的提高也显著增大,并逐渐趋向于一定值。此外,整个非平衡凝固转变时间随过冷度的增大而不断缩短。
The influence of cooling rate and sample purity on non-equilibrium solidification of Fe-B alloy is researched by DSC technology. The evolution results of undercooling and transformation fraction are obtained for different experimental conditions, which are also analyzed and discussed by classic nucleation theory and non-isothermal crystallization kinetics. Results show that the experimental undercooling is gradually increased with the increase of cooling rate and the maximum value can reach 409K. Additionally, undercooling is also increased with the increase of sample purity for the same cooling rate and a limiting exists. Besides that, the whole transformation time is shortened with the increase of undercooling.