MATEC Web Conf.
Volume 326, 2020The 17th International Conference on Aluminium Alloys 2020 (ICAA17)
|Number of page(s)||8|
|Section||New directions in Alloy and Process Development II: Joining, Severe Plastic Deformation, Emerging Processes|
|Published online||05 November 2020|
Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle
1 Welding Engineering and Laser Processing Centre, Cranfield University – United Kingdom
2 Department of Materials, Loughborough University – United Kingdom
An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.
© The Authors, published by EDP Sciences, 2020
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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