Microstructural study of CO2 laser machined heat affected zone of 2024 aluminum alloy

Laser machining is an attractive alternative to traditional machining of Al 2024 because critical operation parameters in aeronautic industry like processing time, versatility, contamination and finish can be improved. The main disadvantage of laser machining is the high temperatures reached by the studied material during the laser processing. A heat affected zone (HAZ) extension lower than 5 mum is observed. The microstructural analysis shows that this HAZ suffers a heating between 548 and 596 degreesC where alpha-liquid phases are present. The high N-2 gas pressure used for the laser cutting induces three types of roughness on this viscous material during the laser processing. To improve this feature, the use of other laser wavelengths and/or power is proposed. The higher quality of the process can also be reached using other aeronautic materials with lower Cu content as 7475 Al alloy. (C) 2002 Elsevier Science B.V. All rights reserved.