Effect of mixing temperature on microstructure of an Al-Si alloy prepared by controlled diffusion solidification  

作　　者：Han Xue Ti-jun Chen Xue-zheng Zhang Guang-li Bi Ying Ma Ren-guo Guan 

机构地区：[1]State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China [2]School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,Liaoning,China

出　　处：《China Foundry》2023年第3期241-252,共12页中国铸造（英文版）

基　　金：supported by the National Key Research and Development Program of China (Grant No.2018YFB2001800)。

摘　　要：The effects of mixing temperature,i.e.,the temperatures of two precursor melts(pure Al and Al-12Si),on the temperature and solute fields of resultant mixture,the nucleation and growth,and the size and morphology of primary grains during controlled diffusion solidification(CDS) of Al-8Si alloy were investigated by using simulation and calculation.The results indicate that a lower mixing temperature is helpful for achieving more supercooled microscale Al-rich pockets in the mixture,and increasing the width and supercooling degree of supercooling zone in the Al-rich pockets,and thus,the nucleation rate.The nuclei grow up in nondendritic mode,resulting in spheroidal,at least,nondendritic grains.In a successful CDS,the superheat degrees of the two precursor melts should be limited within several degrees,and it is not necessary to extra stipulate the superheat degree of target alloy melt(Al-8Si) when the requirement about Gibbs energies of the three melts is matched.Subsequent observation on casting microstructures shows that the employed simulation and calculation processes are reasonable and the achieved results are reliable.

关 键 词：controlled diffusion solidification Al-Si alloy nucleation and growth SUPERCOOLING nondendritic grains 

分 类 号：TG146.21[一般工业技术—材料科学与工程]