材料期刊网

基于纳米热力学理论分析了钢液中非金属夹杂物的形核过程,建立了夹杂物形核的纳米热力学计算模型。通过考虑晶核尺寸对钢液-晶核界面能的影响,推导了钢液-晶核界面能与晶核尺寸之间的关系式;进一步分析晶核尺寸对晶核溶解度的影响,获得了考虑晶核尺寸因素的夹杂物形核过程总Gibbs自由能变化关系式;在此基础上,获得了基于纳米热力学的夹杂物临界晶核半径计算公式。以Al2O3夹杂为例,分别采用纳米热力学和经典形核热力学公式计算了临界晶核半径。结果表明：在相同条件下,基于纳米热力学计算得到的临界晶核半径值均大于经典热力学计算得到的临界晶核半径值;对于用铝终脱氧的一般情况,纳米热力学计算得到Al2O3夹杂物的临界晶核半径为1.40～2.72nm,经典热力学计算值为1.02～1.69nm。研究结果目前难以直接采用试验证实,但可从有关纳米体系热力学研究文献结果得到间接验证。

The nucleation process of non-metallic inclusions in molten steel was analyzed based on nano-thermody namics theory, and calculation model was established. The relational expression of nucleus＇s size dependent interface energy between liquid steel and nucleus was obtained by considering effect of nucleus＇s size on interface energy, and then, the Gibbs free energy change expression of nucleation was established by analyzing influence of nucleus＇s size on its solubility. The mathematic formula for critical radius of nucleus was deduced by differential Gibbs free en ergy change of nucleation. The critical radius of nucleus of Al2O3 inclusion was calculated adopting both nano-ther- modynamics and classical nucleation thermodynamics simultaneously. The results show that numerical value of criti cal radius of nucleus of Al2O3 inclusion based on nano-thermodynamics is greater than numerical value based on clas sical thermodynamics in the same conditions. During the process of terminal aluminum-deoxidation in liquid steel, numerical value of nucleus＇s critical radius of Al2O3 inclusion is approximate 1.40-2. 72 nm by nano-thermodynamics, and value is 1.02-1.69 nm based on classical thermodynamics. The conclusions are consistent of results by molecular dynamic simulation and experiments in relate literatures.