High-strength aluminum alloys hollow billet prepared by two-phase zone continuous casting  

作　　者：Yao-hua Yang Xue-feng Liu Wang-zhang Chen 

机构地区：[1]Beijing Advanced Innovation Center for Materials Genome Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,University of Science and Technology Beijing,Beijing 100083,China [3]Key Laboratory for Advanced Materials Processing of Ministry of Education,University of Science and Technology Beijing,Beijing 100083,China [4]Shunde Graduate School,University of Science and Technology Beijing,Foshan 528399,Guangdong,China

出　　处：《China Foundry》2022年第3期253-262,共10页中国铸造（英文版）

基　　金：the National Natural Science Foundation of China(No.U1703131,No.51674027,No.51974027 and No.52004028);Guangdong Basic and Applied Basic Research Foundation(2019A1515111126);the Fundamental Research Funds for the Central Universities(FRF-TP-18-005C1 and FRF-TP-18-041A1).

摘　　要：The two-phase zone continuous casting(TZCC)technique was used to continuously cast high-strength aluminum alloy hollow billets,and a verified 3D model of TZCC was used to simulate the flow and temperature fields at casting speeds of 2-6 mm·min^(-1).Hollow billets under the same conditions were prepared,and their macro/microstructures were analyzed by an optical microscope and a scanning electron microscope.During the TZCC process,a circular fluid flow appears in front of the mushy zone,and the induction heated stepped mold and convective heat transfer result in a curved solidification front with depressed region near the inner wall and a vertical temperature gradient.The deflection of the solidification front decreases and the average cooling rate in the mushy zone increases with increasing casting speed.Experimental results for a 2D12 alloy show that hot tearing periodically appears in the hollow billet accompanied by macrosegregation near the inner wall at casting speeds of 2 and 4 mm·min^(-1),while macroscopic defects of hot tearing and macrosegregation weaken and the average size of columnar crystals in the hollow billets decreases with further increasing casting speed.2D12 aluminum alloy hollow billets with no macroscopic defects,the finest columnar crystals,and excellent mechanical properties were prepared by TZCC at a casting speed of 6 mm·min^(-1),which is beneficial for the further plastic forming process.

关 键 词：two-phase zone continuous casting high-strength aluminum alloy hollow billet fluid flow heat transfer columnar crystals 

分 类 号：TG146.21[一般工业技术—材料科学与工程]