| METALS AND METAL MATRIX COMPOSITES |
|
|
|
|
|
| Effect of Combinative Addition of Sr and La on Hydrogen Content of SAl 4047 Welding Wire and Mechanical Properties of Welded Joints |
| FEI Wenpan1, XUE Songbai1, CHEN Yuhao1, WU Jie1, WANG Bo1, LIN Zhongqiang2
|
1 College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2 Zhejiang Yuguang Aluminum Material Co., Ltd, Wuyi 321200, China |
|
|
|
|
Abstract The effect of alone or combinative addition of Sr and La on hydrogen content of SAl 4047 welding wire and mechanical properties of 6082 welded joints were investigated. The results show that the secondary dendrite arm spacing of α-Al dendrites in the as-cast microstructure of SAl 4047 welding wire with 0.015% Sr is reduced, and the primary silicon phase is suppressed and disappears, the average size of the eutectic silicon phase is decreased by 84% compared with the wire alloy without Sr or La,it is only 0.56 μm; the hydrogen content of the SAl 4047 welding wire with 0.015% Sr is 0.53 mL/100 g Al in the solid hydrogen test results, the porosity of the 6082 weld joint obtained by using the wire is 1.81%, and the hydrogen content of the welding wire and the porosity of the weld are higher than the limit value. Adding 0.08% La alone can reduce the hydrogen content of SAl 4047 wire to 0.18 mL/100 g Al. The size of primary silicon is reduced in the as-cast microstructure, and the corners are passivated; some α-Al dendrites are transformed into equiaxed crystals. The average size of eutectic silicon particles is 1.24 μm, and the effect of La metamorphism is significantly weaker than that of Sr. When the addition amount of La exceeds 0.08%, it will lead to the formation of needle-like La-rich phase and reduce the mechanical properties of the wire and weld. The as-cast silicon and eutectic silicon phases are dete-riorated completely in the as-cast microstructure of the composite Al-12Si-0.015Sr-0.08La wire. The average size of the eutectic silicon particles is 0.6 μm, and the α-Al phase coexists as columnar and equiaxed crystals; the hydrogen content of the composite wire is 0.31 mL/100 g Al. The porosity of the 6082 weld obtained by welding the wire is 0.38%. The hydrogen content of the wire and the porosity of the weld meet the stan-dard. The test results of the mechanical properties of the joint indicate that the tensile strength, elongation after fracture, and bending fracture angle of the joint obtained by welding the composite wire are 186.7 MPa, 8.4% and 45° to 52°, which are 6.7%, 29.2% and 76% higher than the joint without Sr or La, respectively.
|
|
Published: 26 April 2020
|
|
|
| Fund:This work was supported by the National Natural Science Foundation of China (51675269) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). |
|
Corresponding Authors:
Songbai Xueis currently a level-2 professor and Ph.D. supervisor at the College of Material Science and Technology in Nanjing University of Aeronautics and Astronautics (NUAA). He has focused on welding materials and technology for decades. During these years, he formulated 5 national standards and 5 professional standards of Ministry of Machinery Industry. Besides, he earned more than thirty major research achievements, including a second prize of 2016 State Science and Technology Progress Award, a second prize of 2014 technical invention award of the Ministry of Education, a third prize of National Defense Science and Technology Progress Award, et al.
|
| About author:: Wenpan Feireceived his B.S. degree in material scie-nce and engineering from Nanjing University of Aeronautics and Astronautics (NUAA) in 2016. He is currently pursuing her Master at the College of Material Science and Technology in NUAA under the supervision of Prof. Songbai Xue. His research has focused on advanced welding technology. |
|
|
1 Zheng H, Zhao Y Y. Forging and Stamping Technology, 2016(2), 1(in Chinese).
郑晖, 赵曦雅. 锻压技术, 2016(2),1.
2 Li H Z, Zhang X M, Chen M A, et al. The Chinese Journal of Nonferrous Metals, 2004, 14(6),1990(in Chinese).
李慧中, 张新明, 陈明安, 等. 中国有色金属学报, 2004, 14(6),1990.
3 Li H Z, Guo F F, Liang S P, et al. Transactions of the China Welding Institution, 2008, 29(4), 77(in Chinese).
李慧中, 郭菲菲, 梁霄鹏, 等. 焊接学报, 2008, 29(4), 77.
4 Shi W X, Gao B, Tu G F, et al. Journal of Alloys and Compounds, 2010, 508(2), 480.
5 Xing P, Gao B, Zhuang Y, et al. Journal of Rare Earths, 2010, 28(6), 927.
6 Li Z K, Bian X F, Han N. Special Casting & Nonferrous Alloys, 2007, 27(4), 315(in Chinese).
李贞宽, 边秀房, 韩娜. 特种铸造及有色合金, 2007, 27(4), 315.
7 Li S W, Gao B, Tu G F, et al. Journal of Northeastern University(Natural Science), 2012, 33(11), 86(in Chinese).
李世伟, 高波, 涂赣峰, 等. 东北大学学报(自然科学版), 2012, 33(11), 86.
8 Qiu C, Miao S, Li X, et al. Materials & Design, 2017, 114, 563.
9 Qiao J Y, Wang W Q, Ruan Y, et al. Materials Review: Research Papers, 2018, 32(1), 254.(in Chinese).
乔建毅, 王文权, 阮野, 等. 材料导报:研究篇, 2018, 32(1), 254.
10 Wu Y J, He G Q, Liu X S, et al. Metallic Functional Materials, 2011, 18(5), 45(in Chinese).
武艳君, 何国球, 刘小山, 等. 金属功能材料, 2011, 18(5), 45.
11 Tang P, Wen F L, Zhao Y, et al. Journal of Rare Earths, 2017, 35(5), 485.
12 Radhakrishna K, Seshan S. Cast Metals, 1989, 2(1), 34. |
|
|
|
渝公网安备50019002502923号 © Editorial Office of Materials Reports.
2020, Vol. 34 
