纯铝熔体微观结构演变及液固相关性研究

STUDY ON MICROSTRUCTURE EVOLUTION AND LIQUID\| SOLID CORRELATION OF PURE ALUMINUM MELTS

对液态Ａｌ 在不同冷速下的微观结构及其转变机制进行了分子动力学模拟，模拟采用紧束缚势，得到了不同温度、不同冷速下，Ａｌ 的双体分布函数；采用ＨＡ键型指数法统计了各种小原子团在不同温度下所占比例，得到原子组态变化的重要信息．结果表明，在冷却速率较慢时，液态金属Ａｌ 最终形成晶态，当冷却速率较快时，液态Ａｌ 最终形成非晶态；液态金属中的键对是液态Ａｌ 的基本构成单元，液态Ａｌ 在形成晶体时，１４２１ ，１４２２ 键对起非常重要的作用；而１５５１ ，１５４１

The molecular dynamics simulations have been performed on microstructure and transfer mechanism of liquid Al. The pair distributed function has been attained at different temperatures and cooling rates by means of tight\|binding potential. The proportions of small atom groups of different types have been analyzed by adopting bond pair index method. The result indicates that if the cooling rate is low, crystals will be formed, otherwise, amorphism will occur under relatively high cooling rate. When the liquid Al forms crystal, the bond pairs 1421,1422 play an important role, while the pairs 1551,1541 have the close connection with the formation of amorphism.