本文選題：共晶生長 + 快速凝固�。� 參考：《物理學報》2017年10期

【摘要】：采用落管無容器處理技術(shù)實現(xiàn)了Fe_(67.5)Al_(22.8)Nb_(9.7)三元合金在微重力條件下的快速凝固,獲得了直徑為40—1000μm的合金液滴.實驗中合金液滴的過冷度范圍為50—216 K,冷卻速率隨著液滴直徑的減小由1.23×10~3K·s~(-1)增大到5.53×10~5K·s~(-1).研究發(fā)現(xiàn),Fe_(67.5)Al_(22.8)Nb_(9.7)合金液滴的凝固組織均由Nb(Fe,Al)_2相和(αFe)相組成,且隨著液滴直徑的減小,初生Nb(Fe,Al)_2相由樹枝晶轉(zhuǎn)變?yōu)榈容S晶,共晶組織發(fā)生了約3倍的細化且生長特征由層片共晶向碎斷共晶轉(zhuǎn)變;硬質(zhì)初生Nb(Fe,Al)_2相的析出有效提高了合金的顯微硬度.與電磁懸浮條件下同過冷合金的凝固組織對比發(fā)現(xiàn),落管條件下的合金液滴凝固組織更細化,使得合金顯微硬度提高了2%—6%.
[Abstract]:The rapid solidification of Fe _ S _ 2O _ (67.5) Alac _ (22. 8) NbSZ _ (9. 7) ternary alloy under microgravity conditions has been realized by using the technology of tube-dropping without container. The droplets of the alloy with diameter of 40-1000 渭 m have been obtained. The supercooling range of the alloy droplets is 50-216 K, and the cooling rate increases from 1.23 脳 10 ~ (3) K ~ (-1) to 5.53 脳 10 ~ (5) K ~ (-1) ~ (-1) with the decrease of the droplet diameter. It is found that the solidification structure of the alloy droplets is composed of the (偽 Fe) phase and the (偽 Fe) phase, and with the decrease of the diameter of the droplet, the primary NbFeFeAlN / AlN phase changes from dendrite to equiaxed crystal. The eutectic structure was refined by about 3 times and the growth characteristics were changed from lamellar eutectic to broken eutectic, and the microhardness of the alloy was improved effectively by the precipitation of hard primary NB _ 2O _ (Fe) Al _ 2O _ 2 phase. Compared with the solidified microstructure of the supercooled alloy under the condition of electric magnetic levitation, it is found that the solidified microstructure of the alloy droplet under the condition of falling tube is more refined, which makes the microhardness of the alloy increase by 2-6.
【作者單位】： 西北工業(yè)大學應用物理系;
【基金】：國家自然科學基金(批準號:51327901,U1660108,51671161) 航空科學基金(批準號:2014ZF53069) 陜西省科學技術(shù)研究發(fā)展計劃工業(yè)科技攻關(guān)項目(批準號:2016GY-247)資助的課題~~
【分類號】：TG111.4

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