Al_(50)Si_(50)合金过冷熔体中Si晶体的生长  

GROWTH OF SILICON IN UNDERCOOLED Al_(50)Si_(50) ALLOY MELT

作　　者：葛丽丽[1] 刘日平[1] 王强[1] 王文魁[1] 

机构地区：[1]燕山大学亚稳材料制备技术与科学重点实验室,秦皇岛066004

出　　处：《金属学报》2004年第7期683-688,共6页Acta Metallurgica Sinica

基　　金：国家自然科学基金50171059和中德合作基金GZ032/6资助项目

摘　　要：利用电磁悬浮设备,通过在真空状态下反复加热与冷却处理,获得了Al50Si50(原子分数)合金熔体的深过冷,最大过冷度为320 K.观察了不同过冷度下凝固样品小球的表面及其截面深腐蚀后的组织形貌.过冷度较小时,初生相Si为板条状枝晶形貌,并在其中发现了Al的层状沉积;过冷度较大时,初生相Si转变为粒状形貌.共晶体的形貌也随过冷度的增大转变为离异共晶形态.较大过冷度下,微观组织中发现有晶粒细化现象,这与Si晶体生长受溶质的抑制及初生相Si枝晶的断裂有关.yUndercooled solidification of Al50Si50 (atomic fraction) melt is achieved by repeatedly heating and cooling in electromagnetic levitation facility. A maximum undercooling of 320 K is obtained. Phase morphologies on surfaces and deeply etched sections of the samples solidified at different undercoolings are examined. The primary silicon shows faceted dendrites with stratified deposits of aluminum at small undercooling, but shows granular form without deposits of aluminum at large undercooling. The form of the Al-Si eutectic is also found changed into anomalous form at large undercoolings. The microstructural. refinement is observed at large undercooling, as a result of solute restriction of crystal growth and fragmentation of the primary silicon dendrites.

关 键 词：过冷凝固 AL-SI合金 电磁悬浮 过冷熔体 晶体生长 

分 类 号：TG111[金属学及工艺—物理冶金]