Influence of defocusing amount on the process of Al/Ti cladding above 7050 aluminum alloy based on numerical simulation study

Li Jianzhong; Li Xiangfeng; Zuo Dunwen; Xu Ruihua; Chen Zhu

To study the process of laser clad Al/Ti composite powder above 7050 aluminum, a three dimensional model was established, which can simulate the molten pool size, the temperature gradient, cooling rate and the shape control factor in the condition of different defocusing amount. The simulated results show that the width and depth of the molten pools are positively correlated to the defocusing amount, but negatively correlated after the defocusing amount reaches 20 mm. Both the max temperature gradient numerical value and the best cooling condition appear in the Z direction, which also indicate the growth direction of grains mainly concentrates on the Z direction. The cooling speed reaches the highest and the grain size is small when the defocusing amount is 40 mm. The cooling speed is lowest and grain size is big when the defocusing amount is 80 mm. Moreover, the shape control factor is biggest and the crystal microstructure is columnar when the defocusing amount is 60 mm, and the shape control factor is smallest with cellular crystal microstructure when the defocusing amount 80 mm. Finally, the simulated results about both the grain size and the crystal microstructure of the molten pool are verified by the experiment study.

1. College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics &Astronautics,Nanjing 210016,China

Received Date: 2014-08-05

Rev Recd Date: 2014-09-03

Publish Date: 2015-04-25

Key words:

Abstract: To study the process of laser clad Al/Ti composite powder above 7050 aluminum, a three dimensional model was established, which can simulate the molten pool size, the temperature gradient, cooling rate and the shape control factor in the condition of different defocusing amount. The simulated results show that the width and depth of the molten pools are positively correlated to the defocusing amount, but negatively correlated after the defocusing amount reaches 20 mm. Both the max temperature gradient numerical value and the best cooling condition appear in the Z direction, which also indicate the growth direction of grains mainly concentrates on the Z direction. The cooling speed reaches the highest and the grain size is small when the defocusing amount is 40 mm. The cooling speed is lowest and grain size is big when the defocusing amount is 80 mm. Moreover, the shape control factor is biggest and the crystal microstructure is columnar when the defocusing amount is 60 mm, and the shape control factor is smallest with cellular crystal microstructure when the defocusing amount 80 mm. Finally, the simulated results about both the grain size and the crystal microstructure of the molten pool are verified by the experiment study.

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Reference (19)

[1]
[2]	Wu B, Li M Q, Ma D W. The flow behavior and constitutive equations in isothermal compression of 7050 aluminum alloy [J]. Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2012, 542: 79-87.
[3]	PalDey S, Deevi S C, Alford T L. Cathodic arc deposited thin film coatings based on TiAl intermetallics[J]. Intermetallics, 2004, 12(7-9): 985-991.
[4]
[5]
[6]	Zhu Gangxian, Lin Dichen, Zhang Anfeng. The influence of laser and powder defocusing characteristics on the surface quality in laser direct metal deposition[J]. Optics Laser Technology, 2012, 44(2): 349-356
[7]
[8]	Chen Gang, Li Xiangfeng, Zuo Dunwen. Solidification analysis during laser cladding process based on finite elements[J]. China Mechanical Engineering, 2012, 23(4): 468-473. (in Chinese) 陈刚, 黎向锋, 左敦稳, 等. 基于有限元的激光熔覆凝固过程分析[J]. 中国机械工程, 2012, 23(4): 468-473.
[9]	Tseng W C, Aoh J N. Simulation study on laser cladding on preplaced powder layer with a tailored laser heat source[J]. Optics Laser Technology, 2013, 48: 141-152.
[10]
[11]	Zhang Xue. Studying for ultrasonic casting microstructure and thermal cracking sensitivity of 7050 aluminum alloy round ingot[D]. Changsha: Central South University, 2010. (in Chinese) 张雪. 7050铝合金圆锭超声铸造微观组织及热裂敏感性研究[D]. 长沙: 中南大学, 2010.
[12]
[13]	Tian Rongzhang, Wang Zhutang. Alloy and Processing Manual [M]. Changsha: Central South University Press, 2000. (in Chinese) 田荣璋, 王祝堂. 合金及其加工手册[M]. 长沙: 中南大学出版社, 2000.
[14]
[15]	Zhao G P, Kim J D. Application of 3-D finite element method using Lagrangian formulation to dilution control in laser cladding process[J]. International Journal of Mechanical Sciences, 2003, 45(5): 777-796.
[16]
[17]
[18]	Michael Bass. Laser Material Processing [M]. North-holland Publishing Company, 1983: 239-245.
[19]	Zheng Lijuan, Li Yan, He Dachuan, et al. Analysis on temperature field of multi-path laser claded and microstructure of coatings layer[J]. Infrared and Laser Engineering, 2013, 42(S01): 52-57. (in Chinese) 郑丽娟, 李燕, 何大川, 等. 激光多道熔覆温度场及熔覆层组织分析[J]. 红外与激光工程, 2013, 42(S01): 52-57.

Influence of defocusing amount on the process of Al/Ti cladding above 7050 aluminum alloy based on numerical simulation study

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