摘要
为了研究熔体热历史对Al-80%Si合金凝固特性的影响,采用高速摄影仪和扫描电镜分别对Al-80%Si合金熔体在不同过热温度与保温时间下初生硅结晶过程进行了动态观测,获得了初生硅结晶形貌与过热温度和保温时间的关系.研究结果表明:随过热温度的升高和保温时间的延长,Al-80%Si合金凝固时过冷度增大,初生硅小平面生长方式减弱.在2min保温时间下过热温度超过100K或在50K过热温度下保温时间超过5min时,初生硅形态由粗大的长条多面体变为均匀细小的等轴多面体.说明熔体热历史可以有效地细化Al-80%Si合金中的初生硅.
In order to study the effects of melt thermal history on the solidificallon characteristics of Al-80%Si alloy,this experiment was conducted to study the dynamic observation of Al-80%Si alloy at different super-heated temperature and holding time of primary silicon crystallization process,to get the relationship of the primary silicon crystal morphology with super-heated temperature and holding time. The effect of melt thermal history elements on the solidification behavior and the as-solidified microstructure for the Al-80 % Si alloy prepared by electromagnetic levitation method was investigated by using high speed camera and scanning electron microscope. It was found that with the extending of super- heated temperature and holding time, the undercooling of Al-80%Si alloy was lager, lateral mode of primary silicon would decrease. The morphology of the primary silicon changed from large elongate polyhedron to small isometric polyhedron when the super-heated temperature over 100 K and the holding time over 5 rain. It is explained that the melt thermal history effectively refines the primary silicon in Al- 80%Si alloy.
出处
《西安工业大学学报》
CAS
2015年第4期322-328,共7页
Journal of Xi’an Technological University
基金
国家自然科学基金项目(51071115
51171136)
国家重点基础研究发展计划项目(2011CB610403)
