摘要
采用自蔓延高温合成 (SHS)技术直接合成了Al 80 %TiC和Al 5 0 %TiC晶粒细化剂。研究了这两种细化剂的相组成、结构及对工业纯铝的晶粒细化效果 ,并与商用Al 5Ti 1B细化剂进行了对比。结果表明 :合成的细化剂由TiC和α (Al)两相组成 ,TiC粒子的尺寸和分布对细化剂的晶粒细化效果有显著影响。Al 80 %TiC细化剂中TiC粒子尺寸较大 (2～ 5 μm)且呈聚集成团分布 ,其晶粒细化效果较差。合成的Al 5 0 %TiC细化剂的晶粒细化效果略优于Al 5Ti 1B细化剂。加入 0 .1%的该细化剂就能使凝固试样的结构由粗大的柱状晶转变成细小的等轴晶 (平均晶粒尺寸 12 0 μm) ,且这种晶粒细化效果可保持 90min。SEM和TEM分析显示 ,Al 5 0 %TiC细化剂中原位合成的TiC粒子具有亚微米尺寸 (0 .4～ 0 .9μm) ,且在高温铝液中具有较强的稳定性 。
Al-80%TiC and Al-50%TiC grain refiners were directly synthesized by self-propagating high-temperature synthesis (SHS) technology. The phase components and microstructures of the synthesized grain refiners were examined by XRD and SEM, and their grain refining performances for commercially pure aluminum were also evaluated and compared with commonly used Al-5Ti-1B grain refiner. The results show that the SHS grain refiners consist of TiC and α-(Al), and that the size and distribution of TiC particles have significant influence on the grain refining properties of the SHS grain refiners. Al-80%TiC has poor grain refining effect because of coarser size (2～5 μm) and agglomeration of the synthesized TiC particles, whereas Al-50%TiC exhibits higher grain refining performance than Al-5Ti-1B . The addition of SHS Al-50%TiC grain refiner to the molten aluminum in the amount of 0.1% might transform the structure of the solidified samples from coarse columnar grains to fine equiaxed grains (average grain size 120 μm), and this grain refining effect could be maintained for 90 min at 1 003 K. SEM and TEM examinations show that submicron (0.4～0.9 μm) TiC particles in SHS Al-50%TiC grain refiner exhibit high thermodynamic stability in liquid aluminum, thereby affording the grain refiner excellent grain refining performance and high resistance to grain refining fading.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2002年第5期977-981,共5页
The Chinese Journal of Nonferrous Metals
基金
武汉市优秀青年"晨光计划"基金资助项目 ( 2 0 0 15 0 0 5 0 2 8)
