| YE Xiu,WU Mei-ping,MIAO Xiao-jin,LU Pei-pei.Influence of Laser Remelting on Forming Quality of Ti-6Al-4V Fabricated by Selective Laser Melting[J],50(8):301-310 |
| Influence of Laser Remelting on Forming Quality of Ti-6Al-4V Fabricated by Selective Laser Melting |
| Received:July 03, 2020 Revised:November 19, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.08.028 |
| KeyWord:selective laser melting laser remelting Ti-6Al-4V density wear resistance |
| Author | Institution |
| YE Xiu |
School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| WU Mei-ping |
School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| MIAO Xiao-jin |
School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| LU Pei-pei |
School of Mechanical Engineering, Jiangnan University, Wuxi , China |
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| Abstract: |
| In view of the problems such as porosity defects and poor forming quality of Ti-6Al-4V alloy formed by (Selective laser melting, SLM), the processing method of “initial scanning+low laser power remelting” is proposed to study the influence mechanism of laser remelting on the forming quality and the effect of remelting power on forming quality to optimize the parameters. In this paper, the molten pool and temperature field distribution of SLM processing and laser remelting process are studied based on ANSYS software. The morphology, distribution of the defects and the microstructure of cross-section are observed by metallographic microscope. The microhardness and friction and wear properties are tested by microhardness tester and friction and wear tester, respectively. The results indicate that with the increase of laser remelting power, the size of remelting pool increased, and the temperature gradient transition gradually slowed down. The defects formed in the initial scanning could be filled after remelting, and the porosity of the specimens decreased gradually. When the laser remelting power was 120 W, the density of the formed part reached 99.89%; When the laser remelting power was 100 W, the hardness of the formed parts reached 444.0HV0.3, which was 21.0% higher than that of the sample not remelted, and the average friction coefficient was 0.396, which was 13.73% lower than that of the sample not remelted. We can conclude that laser remelting can effectively improve the density, microhardness and friction and wear properties of SLM parts. With the increase of laser remelting power, the range of molten pool is enlarged, and the size of pores formed in the process of first scanning decreases obviously. The grain boundary of β phase expands, the size of acicular martensite increases, and the microhardness is improved. When the remelting power is 140 W, the effect of molten pool is intense and the solid shrinkage in solidification process makes the forming quality decrease. |
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