Study on Process Parameter Optimization in Laser Additive Manufacturing of 7075 Aluminum Alloy

Shaoting Cao; Weihao Cheng; Lan Zhang

doi:10.6919/ICJE.202506_11(6).0022

Authors

Shaoting Cao
Weihao Cheng
Lan Zhang

DOI:

https://doi.org/10.6919/ICJE.202506_11(6).0022

Keywords:

7075 Aluminum Alloy; Laser Powder Bed Fusion; Microscopic Structure.

Abstract

7075 aluminum alloy has become one of the commonly used lightweight alloys in aerospace applications due to its low density, high specific strength and stiffness, and excellent corrosion resistance. However, owing to its high thermal conductivity, high laser reflectivity, and wide solidification interval, 7075 aluminum alloy is prone to metallurgical defects such as intergranular solidification cracks during laser powder bed fusion (LPBF) processing, which severely affects the forming quality and mechanical properties of the fabricated components. To address these scientific challenges, this study employed LPBF technology to fabricate 7075 aluminum alloy, exploring its optimized processing window and revealing the formation mechanisms of multi-scale metallurgical defects. The effects of varying scanning speeds, laser powers, and laser energy densities on the forming quality and mechanical properties of LPBF-processed 7075 aluminum alloy were systematically investigated. The results indicate that as the laser energy density increases from 119 J/mm³ to 298 J/mm³, the relative density of the samples initially rises and then stabilizes. The optimal relative density of 98.5% is achieved at a laser energy density of 295 J/mm³. Meanwhile, the microhardness of the fabricated specimens significantly increases from 85±3 HV_0.1 to 104±3 HV_0.1 with higher energy densities. The optimized process parameters are identified as a laser energy density of 298 J/mm³, a laser power of 425 W, and a scanning speed of 800 mm/s.

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References

[1] Wang Guangchun. Additive Manufacturing Technology and Application Examples [M]. China Machine Press, 2014.

[2] Gu D D, Meiners W, Wissenbach K, et al. Laser additive manufacturing of metallic components: Materials, processes and mechanisms[J]. International Materials Reviews, 2012, 57(3): 133–164.

[3] Gu Dongdong, Shen Yifu. Current status and prospects of rapid prototyping of metal parts based on selective laser melting [J]. Aeronautical Manufacturing Technology, 2012, 8: 6.

[4] Abd-Elaziem W, Elkatatny S, Abd-Elaziem A, et al. On the current research progress of metallic materials fabricated by laser powder bed fusion process: a review[J]. Journal of Materials Research and Technology, 2022, 20: 681–707.

[5] Li Y, Gu D. Parametric analysis of thermal behavior during selective laser melting additive manufacturing of aluminum alloy powder[J]. Materials and Design, 2014, 63: 856–867.

[6] Azizi A, Chen X B, Gou F L, et al. Selective laser melting of metal structures onto graphite substrates via a low melting point interlayer alloy[J]. Apply Materials Taday, 2022, 26: 101334.

[7] Chen Keyu, Xu Limin, Gan Jie. Influence of laser power on microstructure and mechanical properties of AlSi10Mg fabricated by selective laser melting [J]. Laser & Optoelectronics Progress, 2021, 58(13): 347–355.

[8] Miranda G, Faria S, Bartolomeu F, et al. A study on the production of thin-walled Ti6Al4V parts by selective laser melting[J]. Journal of Manufacturing Processes, 2019, 39: 346–355.

[9] Al-Rubaie K S, Melotti S, Rabelo A, et al. Machinability of SLM-produced Ti6Al4V titanium alloy parts[J]. Journal of Manufacturing Processes, 2020, 57: 768–786.

[10] Zhang H, Gu D, Ma C, et al. Effect of post heat treatment on microstructure and mechanical properties of Ni-based composites by selective laser melting[J]. Materials Science and Engineering A, 2019, 765: 138294.

[11] Gu D, Zhang H, Dai D, et al. Laser additive manufacturing of nano-TiC reinforced Ni-based nanocomposites with tailored microstructure and performance[J]. Composites Part B: Engineering, 2019, 163: 585–597.

[12] Grzesiak D, AlMangour B, Krawczyk M, et al. Selective laser melting of TiC reinforced stainless steel nanocomposites: Mechanical behaviour at elevated temperatures[J]. Materials Letters, 2019, 256: 126633.

[13] Yan Q, Song B, Shi Y. Comparative study of performance comparison of AlSi10Mg alloy prepared by selective laser melting and casting[J]. Journal of Materials Science and Technology, 2020, 41: 199–208.

[14] Liu X, Zhao C, Zhou X, et al. CNT-reinforced AlSi10Mg composite by selective laser melting: microstructural and mechanical properties[J]. Materials Science and Technology (United Kingdom), 2019, 35(9): 1038–1045.

[15] Williams J C, Starke E A. Progress in structural materials for aerospace systems[J]. Acta Materialia, 2003, 51(19): 5775–5799.

[16] Kaufmann N, Imran M, Wischeropp T M, et al. Influence of process parameters on the quality of aluminium alloy en AW 7075 using Selective Laser Melting (SLM)[J]. Physics Procedia, 2016, 83: 918–926.

[17] Babu A P, Kairy S K, Huang A, et al. Laser powder bed fusion of high solute Al-Zn-Mg alloys: Processing, characterisation and properties[J]. Materials and Design, 2020, 196.

[18] Louvis E, Fox P, Sutcliffe C J. Selective laser melting of aluminium components[J]. Journal of Materials Processing Technology, 2011, 211(2): 275–284.

[19] Stopyra W, Gruber K, Smolina I, et al. Laser powder bed fusion of AA7075 alloy: Influence of process parameters on porosity and hot cracking[J]. Additive Manufacturing, 2020, 35: 101270.

[20] Wang Dayuan, Li Xiaoqiang, Lai Jiaming, et al. Study on microstructure, properties, and cracks of 7075 aluminum alloy fabricated by selective laser melting [J]. Applied Laser, 2019, 39.

[21] Gu D, Shen Y. Effects of processing parameters on consolidation and microstructure of W-Cu components by DMLS[J]. Journal of Alloys and Compounds, 2009, 473(1–2): 107–115.

[22] Arafune K, Hirata A. Thermal and solutal marangoni convection in In-Ga-Sb system[J]. Journal of Crystal Growth, 1999, 197(4): 811–817.

[23] Yogamalar R, Srinivasan R, Vinu A, et al. X-ray peak broadening analysis in ZnO nanoparticles[J]. Solid State Communications, 2009, 149(43–44): 1919–1923.

[24] Prasad A, Yuan L, Lee P, et al. Towards understanding grain nucleation Manufacturing solidification conditions under Additive[J]. Acta Materialia, 2020, 195: 392–403.