Towards relieving center segregation in twin-roll cast Al-Mg-Si-Cu strips by controlling the thermal-mechanical process  

作　　者：Shao-You Zhang Xuan Wang Yuan-Ting Mo Cheng Wang Tuo Cheng Orest Ivasishin Pin-Kui Ma 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,Changchun 130025,China [2]International Center of Future Science,Jilin University,Changchun 130012,China

出　　处：《Journal of Materials Science & Technology》2023年第17期31-40,共10页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51790483,51790485,51901029,and U2241232);financial support came from The Sci-ence and Technology Development Program of Jilin Province(Nos.20200401030GX,20200201002JC,and 20200401025GX).

摘　　要：Serious center segregation greatly limits the application of twin-roll casting(TRC)technology for produc-ing 6xxx alloy strips.Herein,Al-0.9Mg-0.6Si-0.2Cu-0.1Fe(wt.%,6061)strips with different thicknesses were fabricated by TRC,and we found that the center segregation was well relieved with the thick-ness increased from 3 mm to 4 mm.To reveal the mechanisms of mitigation of center segregation in the 4 mm strip,various techniques including solidification simulation,crystallographic calculation,elec-tron backscatter diffraction(EBSD),and electron probe micro-analyzer(EPMA)were utilized.The re-sults disclosed that the Fe-containing phase in the 3 mm strip wasπ-AlFeMgSi,while the counterpart in the 4 mm strip wasα-AlFeSi.Theα-AlFeSi could serve as nucleation substrates for Mg_(2)Si and Q-AlCuMgSi phases,thus promoting the uniform distribution of elements and preventing the accumulation of phases in the center region.Three matching planes between theα-AlFeSi and Q/Mg_(2)Si were exam-ined as:(1120)_(α-AlFeSi)//(0001)_(Q),(0001)_(α-AlFeSi)//(110)_(Mg2Si),and(1120)_(α-AlFeSi)//(110)_(Mg2Si).Meanwhile,the smaller roll separating force during the TRC process in the 4 mm strip could weaken the force-induced liquid flow behavior in the semi-solid region,which is the other reason for the alleviation of center seg-regation.Owing to the elimination of the center segregation,a more excellent fracture elongation was achieved in the as-homogenized 4 mm strip(∼29%)compared with the counterpart of the 3 mm strip(∼20%).This work may provide a strategy to eliminate the center segregation,thus further promoting the application of TRC process and producing high-performance Al alloy strips efficiently.

关 键 词：Aluminum alloy Twin-roll casting Center segregation Fe-containing phase Nucleation substrate 

分 类 号：TG139.8[一般工业技术—材料科学与工程]