连续升温、降温过程中纯Fe的微观结构分析  

ANALYSIS OF THE MICROSTRUCTURE OF Fe DURING CONTINUOUS HEATING AND COOLING PROCESS

作　　者：高帅[1] 吴永全[1] 沈通[1] 张宁[1] 王赛[1] 

机构地区：[1]上海大学上海市现代冶金及材料制备重点实验室,上海200072

出　　处：《上海金属》2012年第5期1-6,共6页Shanghai Metals

基　　金：国家自然科学基金项目(50504010和50974083);国家自然科学基金委员会和上海宝钢集团公司联合基金项目(50774112);上海市青年科技启明星计划项目(07QA14021);长江学者和创新团队发展计划项目(IRT0739);上海市教育委员会科研创新项目(09YZ24)资助

摘　　要：通过分子动力学模拟,采用较先进的键型指数法HA及原子团类型指数法CTIM-2,对Fe连续升温、降温过程中微观结构进行模拟研究。结果表明:连续升温过程,Fe的微观结构变化是bcc→fcc\hcp→bcc→液体;连续降温过程,Fe的微观结构变化是液体→fcc\hcp。Fe凝固结束没有形成大量的高温bcc晶体,原因是在高温液态中bcc结构原子稳定性较差,fcc和hcp结构原子更易稳定存在。此外,温度变化速率过快,可诱导晶体生长过程中发生层错,促使Fe在升温、降温过程出现fcc和hcp晶体的交替分层分布,这与fcc和hcp晶体的原子能量相近、晶体的致密度相同、原子空间堆垛方式局部相同有关。The microstructure of Fe during continuous heating and cooling process was analyzed by the Honeyeutt-Anderson （HA） bond pair analysis technique and the cluster type index method （CTIM-2） in molecular dynamics （MD） simulation. During the heating process, the structure variation of Fe was as this： bcc→ fcc／hcp →bcc→liquid. However, the changing of liquid phase→fcc ／hcp occurred during the process of cooling down. After solidification, no many bcc crystals formed because the stability of bec structure was poor at high temperature. In contrast, the fce and hcp structure were more stable than bcc structure. Moreover, the large temperature changing rate could lead to stacking fault in the process of crystal growth, and fcc and hcp crystals were distributed by turns, which mainly related to the similarity of their atomic energy, the crystal density and atomic space spacing pattern.

关 键 词：原子团类型指数法 键型指数法 Fe微观结构 分子动力学模拟 

分 类 号：O632.12[理学—高分子化学]