Laser-Based Directed Energy Deposition of Ceramic Nanoadditivated AA7075 Powder Alloys

Abstract:

AA7075 is one of the most resistant aluminium alloys, so it is frequently used in very demanding industries as aeronautics or defence. However, the 7075 alloy falls into the non-weldable category thus hardly processable through additive manufacturing processes, and specially on laser-based DED (Directed Energy Deposition). The low absorption together with cracking behaviour remain a challenge for the industrialisation of these processes. Alloying with minor elements or addition of nano-reinforcement have been proven as a successful approach to increase its manufacturability. In this work, the feasibility of printing 7075 with nano-TiC as additive was evaluated. Two compositions with 0.5 and 2% in weight were developed by dry mixing. The powders were characterized by scanning electron microscopy (SEM) and flowability was compared with the unreinforced alloy. With the optimal laser process parameters, 3D coupons were printed to be characterized microstructurally, thermally, and mechanically. Process monitoring using thermal and high-speed cameras was carried out to gain insight into the thermal behaviour of the melt-pool and resulting process stability. After printing, aspect ratio of single tracks was measured, and dilution was also evaluated. Although addition of 0.5% of n-TiC promotes a slight improvement on the alloy, allowing it to be mechanically tested, it still presents some defects as porosity. By increasing the content up to 2%, both the quality and the mechanical performance were enhanced significantly.

• Periodical: Key Engineering Materials (Volume 964)
• Pages: 157-162
• DOI: https://doi.org/10.4028/p-HM0cq9
• Online since: November 2023
• Authors: Pilar Rey*, Alejandro Lazaro Martinez, Gemma Castro Regal, Raul Sanchez Cruz, Clovis Alleaume, Camilo Prieto Rio, Thomas Pabel, Erhard Kaschnitz
• Keywords: 7075, Aluminium Alloys, Ceramic Nanoadditive, Laser-Based Directed Energy Deposition

References

[1] Pujari, K. S. & Patil, D. V. A review on GTAW technique for high strength aluminium alloys (AA 7xxx series), Int. J. Eng. Res. Technol. 2 8 (2013) 2477–2490.

[2] M. Holzer et al., Change of hot cracking susceptibility in welding of high strength aluminum alloy AA 7075, Physics Procedia 83 (2016) 463 – 471.

DOI: 10.1016/j.phpro.2016.08.048

[3] Bekir Çevik, Gas tungsten arc welding of 7075 aluminum alloy: microstructure properties, impact strength, and weld defects, Mater. Res. Express, 5 (2018) 066540.

DOI: 10.1088/2053-1591/aacbbc

[4] Dixit, S.; Liu, S. Laser Additive Manufacturing of High-Strength Aluminum Alloys: Challenges and Strategies. J. Manuf. Mater. Process. 6 (2022) 156.

DOI: 10.3390/jmmp6060156

[5] Arnold Mauduit, et al., Study of the suitability of aluminum alloys for additive manufacturing by laser powder-bed fusion, U.P.B. Sci. Bull., Series B, 79 4 (2017) 219-238

[6] Sánchez Amaya JM. Laser welding of light metal alloys: aluminium and titanium alloys, Handbook of Laser Welding Technologies (2013) 215- 254.

DOI: 10.1533/9780857098771.2.215

[7] Sokoluk, M., Cao, C., Pan, S. et al. Nanoparticle-enabled phase control for arc welding of unweldable aluminum alloy 7075. Nat Commun 10 (2019) 98.

DOI: 10.1038/s41467-018-07989-y

[8] Martin, J., et al. 3D printing of high-strength aluminium alloys, Nature 549 (2017) 365–369.

[9] Lin, TC., Cao, C., Sokoluk, M. et al. Aluminum with dispersed nanoparticles by laser additive manufacturing, Nat Commun. 10 (2019) 4124.

[10] Qu, M., Guo, Q., Escano, L.I. et al. Controlling process instability for defect lean metal additive manufacturing, Nat Commun 13 (2022) 1079.

DOI: 10.1038/s41467-022-28649-2

[11] Xi, L.; et al., Microstructure development, tribological property and underlying mechanism of laser additive manufactured submicro-TiB2 reinforced Al-based composites. J. Alloys Compd. 819 (2020) 152980.

DOI: 10.1016/j.jallcom.2019.152980

[12] Wen, X. et al., Laser solid forming additive manufacturing TiB2 reinforced 2024Al composite: Microstructure and mechanical properties. Mater. Sci. Eng. A 745 (2019) 319–325.

DOI: 10.1016/j.msea.2018.12.072

[13] Information on https://zenodo.org/record/5469946#.ZGOrU0_P1PY.

[14] https://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma7075t6

[15] Shen, L., et al., Synergistic strengthening of FeCrNiCo high entropy alloys via micro-TiC and nano-SiC particles. Mater. Today Commun. (2021) 26 101729.

DOI: 10.1016/j.mtcomm.2020.101729