Substantial grain refinement of Al-Mn-Si alloys me diate d by collaborative effect of Al-5Ti-1B refiner and sub-rapid solidification  

作　　者：Yong-Si Wei Cheng Wang Jiang You Dong Qiu Yipeng Gao Hong Xu Jin Xu Hui-Yuan Wang 

机构地区：[1]Key Laboratory of Automobile Materials of Ministry of Education&School of Materials Science and Engineering,Nanling Campus,Jilin University,No.5988 Renmin Street,Changchun,130025,China [2]Center for Additive Manufacturing,School of Engineering,RMIT University,Melbourne,VIC,3001,Australia [3]State Key Laboratory of Reliability and Intelligence of Electrical Equipment,School of Material Science and Engineering,Hebei University of Technology,Tianjin,300130,China

出　　处：《Journal of Materials Science & Technology》2024年第20期230-239,共10页材料科学技术（英文版）

基　　金：Financial supports from the National Natural Science Foun-dation of China(Nos.52222409,52074132,U19A2084,and U22A20109)are greatly acknowledged;Partial financial support came from the National Key Research and Development Program(No.2022YFE0122000);the Interdisciplinary Integration and Inno-vation Project of JLU(No.JLUXKJC2021ZZ08);the Fundamental Research Funds for the Central Universities,JLU.

摘　　要：The mechanical properties of as-cast metallic materials depend strongly on the size and shape of grains,which are critical microstructural parameters dictated by the interplay of nucleation and growth of crys-talline solids during solidification.In our experiments,the microstructure transition from coarse colum-nar crystals into fine equiaxed crystals for dilute Al-Mn-Si alloys was achieved by using sub-rapid so-lidification with the addition of Al-5Ti-1B grain refiner.The average grain size of Al alloy was reduced from a millimeter size to 73μm.Through temperature gradient calculation,we found that the acqui-sition of fine equiaxed crystals could be attributed to the existence of a high number density of TiB2,acting as effective nucleation sites with an increase in total undercooling.Furthermore,the curvature su-percooling,constitutional undercooling,thermal undercooling,and kinetic undercooling during sub-rapid solidification were quantitatively determined for given solidification rates.Our results showed that con-stitutional undercooling,rather than thermal undercooling,was primarily responsible for the formation of fine equiaxed grains,with the assistance of Al-5Ti-1B grain refiner.This work provides a new insight into the grain refining mechanism under sub-rapid solidification.

关 键 词：Aluminum alloys Sub-rapid solidification Columnar-to-equiaxed transition Grain refinement 

分 类 号：TG14[一般工业技术—材料科学与工程]