交变磁场作用下特种合金的凝固特性  

Solidification characteristics of special alloys under alternating magnetic field

作　　者：张丰收[1] 寇宏超[2] 李金山[2] 贺跃辉[1] 傅恒志[2] 刘林[2] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《粉末冶金材料科学与工程》2005年第4期205-210,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金重大项目(59995440);国家重点基础研究发展规划资助项目(G20000672022)

摘　　要：以高温合金(K403)为实验材料,对中、小尺寸特种合金在交变磁场作用下成形过程的凝固特性进行研究,以期加深对凝固组织细化机理的认识,进而实现对凝固组织的优化控制。在研究过程中首先试验、研究了高温合金无接触和软接触电磁成形的凝固特性,探讨了电磁致流、磁化套以及抽拉速度对凝固组织的影响,进而分析了该特种合金电磁成形凝固组织的细化机理。结果表明:使用磁化套可以获得平直、细化的定向枝晶组织;在该文实验条件下,当抽拉速度为9.8mm/min时,一次枝晶间距能减小到80μm;电磁致流导致二次枝晶臂脱落是无接触电磁成形凝固组织细化的主要机理,而枝晶尖端开裂是软接触电磁成形凝固组织细化的主要机理。Using superalloy, K403, as experimental material to investigate the solidification characteristics of the mediate/small special alloy under alterating magnetic field with the aim of understanding further the fine-crystallization mechanism and the optimization way of the solidification micro-structure. In the process of investigation, the solidification characteristics of the contactless and the soft-contact electromagnetic shaping, as well as the affection of electromagnetic stirring, susceptors and drawing speed were experimentally studied; and thereby the fine-crystallization mechanism of the solidification micro-structure of electromagnetic shaping was analyzed. The results show that, the tenuous and parallel dendrite can be obtained by using susceptors; the first dendrite arm spacing is decreased from 120μm to 80μm while the drawing speed increased from 3.2mm/min to 9.8mm/min; the main mechanism of the solidification microstructure for the contactless electromagnetic shaping is the secondary dendrite arm's peeling off amd that for the soft-contact electromagnetic shaping is the dendrite point's cracking.

关 键 词：特种合金 无接触 软接触 电磁成形 磁化套 凝固 

分 类 号：TG249[金属学及工艺—铸造]