纯铝熔体微观结构演变及液固相关性研究…

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键对对非晶的形成有重要的影响 关键词：

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

The molecular dynamics simulations have been performed on microstructure and tra n sfer mechanism of liquid Al. The pair distributed function has been attained at different temperatures and cooling rates by means of tight－binding potential. T he proportions of small atom groups of different types have been analyzed by ado pting bond pair index method. The result indicates that if the cooling rate is l ow　 crystals will be formed　otherwise　amorphism will occur under relatively hi gh 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.