摘要
形核是凝固过程的重要阶段.由经典形核理论及其最新进展可知,对应不同的凝固条件,合金熔体中可能出现三种形核方式,即连续形核、位置饱和及自由生长.着眼于过冷合金熔体非平衡凝固中形核方式的竞争,包括连续形核与非热形核(位置饱和与自由生长)的竞争、单点形核与多点形核的竞争、均质形核与异质形核间的竞争,对不同合金系的形核方式进行了讨论.通过相关实验结果及分析证实了上述竞争的存在,进而提出了一些确定形核机制的判据.
Nucleation plays a key role in solidification processing. The present overview focuses on a series of competitions incorporated in nucleation upon non-equilibrium solidification of bulk undercooled alloy melt. According to the classical nucleation theory and the newly developments in nucleation field, three nucleation modes, namely, continuous nucleation, site saturation and free growth are proposed for different solidification conditions. Competition of nucleation modes, which consists of continuous nucleation and athermal nucleation （site saturation and free growth）, competition between one point and copious nucleation, competition between homogeneous and heterogeneous nucleation, were separately discussed in various alloy systems. At the same time, experiment evidences were given and analyzed to prove these competitions. Additionally, some criterions for determining nucleation mechanism were also proposed.
出处
《西安工业大学学报》
CAS
2008年第4期341-355,共15页
Journal of Xi’an Technological University
基金
新世纪优秀人才支持计划(NCET-05-0870)
国防基础研究项目(A2720060295)
留学回国人员基金(N6CJ0002)
西北工业大学基础研究基金
科技创新基金
霍英东青年教师基金(111052)
国家自然科学基金项目(50501020
50771084
50395103)
关键词
形核
过冷
非平衡凝固
形核方式的竞争
nucleatiom undercooled
non-equilibrium solidificatiom competition of nucleation modes
