及其晶粒細(xì)化效果
(1． 華中科技大學(xué) 模具技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，
武漢 430074；
2． 武漢理工大學(xué) 材料科學(xué)與工程學(xué)院，武漢 430070)
摘 要: 采用自蔓延高溫合成（SHS）技術(shù)直接合成了Al-80%TiC和Al-50%TiC晶粒細(xì)化劑。 研究了這兩種細(xì)化劑的相組成、結(jié)構(gòu)及對(duì)工業(yè)純鋁的晶粒細(xì)化效果，并與商用Al-5Ti-1B細(xì)化劑進(jìn)行了對(duì)比。結(jié)果表明：合成的細(xì)化劑由TiC和α-（Al）兩相組成，TiC粒子的尺寸和分布對(duì)細(xì)化劑的晶粒細(xì)化效果有顯著影響。Al-80%TiC細(xì)化劑中TiC粒子尺寸較大（2～5μm）且呈聚集成團(tuán)分布，其晶粒細(xì)化效果較差。合成的Al-50%TiC細(xì)化劑的晶粒細(xì)化效果略優(yōu)于Al-5Ti-1B細(xì)化劑。加入0.1%的該細(xì)化劑就能使凝固試樣的結(jié)構(gòu)由粗大的柱狀晶轉(zhuǎn)變成細(xì)小的等軸晶（平均晶粒尺寸120μm），且這種晶粒細(xì)化效果可保持90min。SEM和TEM分析顯示，Al-50%TiC細(xì)化劑中原位合成的TiC粒子具有亞微米尺寸（0.4～0.9μm），且在高溫鋁液中具有較強(qiáng)的穩(wěn)定性，從而賦予該細(xì)化劑良好的晶粒細(xì)化效果和強(qiáng)的抗晶粒細(xì)化衰退能力。
關(guān)鍵字: 自蔓延高溫合成；Al-TiC晶粒細(xì)化劑；工業(yè)純鋁；晶粒細(xì)化
performances for commercially pure aluminum
FU Zheng-yi2, WEI Bo-kang1
（1. State Key Lab of Die Technology,
Huazhong University of Science & Technology,
Wuhan 430074, China;
2. School of Materials Science and Engineering,
Wuhan University of Technology,
Wuhan 430070, China）
Abstract: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 (2～5μm) 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 120μm), and this grain refining effect could be maintained for 90min at 1003K. SEM and TEM examinations show that submicron (0.4～0.9μm) 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.
Key words: SHS; Al-TiC grain refiner; commercially pure aluminum; grain refinement
