CC BY
6*
ALT'23
The 30th International Conference on Advanced Laser Technologies
LM-I-13
Influence of high-energy laser irradiation on structural and phase transformations in aluminum-lithium alloys during laser welding
A.G. Malikov
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk
Laser welding is widely recognized as an advanced technology for joining materials using a high-power, high-density energy laser beam. Laser welding offers several advantages, such as high speed, high precision, a small heat-affected zone, no need for vacuum chambers, flexibility, and the ability to automate the process. The process of laser welding involves several physical phenomena, including the interaction of the laser with the material, multiple reflections of the laser radiation inside the vapor-gas channel, phase transitions, liquid and gas flow, and heat and mass transfer. In aerospace and rocket engineering, the main method for joining alloys is riveting, but this method has several disadvantages. Riveting technology is characterized by high labor intensity, and the process is accompanied by significant noise and vibration that can be harmful to humans, industrial buildings, and structures.
Currently, riveting is being replaced by welding as a leading technology in the field. According to estimates by VIAM, the transition to third-generation Al-Li alloys with a replacement of riveted joints with welded ones will result in a weight reduction of aircraft structures (Il-112V, SSJ-New) up to 25% [1-2]. However, there is a problem related to the static-mechanical characteristics (tensile strength, yield strength, and elongation) of laser-welded joints, which are directly related to the structural and phase changes of the original material as a result of laser processing. These characteristics remain low, constituting only 50-80% of the original alloy values [3]. The complexity of these processes is due to the simultaneous occurrence of a significant number of physical and chemical processes involving liquid, solid, and gaseous phases, as well as high temperatures and complex hydrodynamic and thermal flows.
This work is for the first time aimed at solving a complex scientific problem associated with achieving maximum static mechanical characteristics of permanent laser welded joints new class of materials - Al-Li alloys of the third generation. This became possible by controlling the structure and phase composition of the weld as a result of optimizing the process of laser exposure and for the first time used to control the evolution of the structural-phase composition of the weld of aluminum alloys, through the use of a modern independent diagnostic method: synchrotron radiation diffractometry, on a "megascience" class facility. The influence of the energy parameters of laser action on the change in the structure and phase composition of the weld material depending on the alloying system and the thermophysical properties of aluminum-lithium alloys of the third generation is shown. It is also shown that the subsequent optimization of post-heat treatment in the form of hardening and artificial aging makes it possible to obtain the strength of laser welded joints at the level of the strength of the base material.
The research was carried out with the support of a grant from the Russian Science Foundation № 23-7900037, https://rscf.ru/project/23-79-00037/.
[2] Malikov A., Orishich A., Bulina N., Karpov E., Sharafutdinov M. Effect of post heat treatment on the phase composition and strength of laser welded joints of an Al-Mg-Li alloy, Materials Science and Engineering A. 2019, vol. 765. Art. 138302 (8 p.).
[3] Malikov A., Orishich A., Vitoshkin I., Bulina N., Karpov E., Gutakovskii A., Batsanov S., Ancharov A., Tabakaev R. Effect of the structure and the phase composition on the mechanical properties ofAl-Cu-Li alloy laser welds, Materials Science and Engineering: A. 2021, vol. 809. Art. 140947 (16 p.)..
[1] Malikov A., Golyshev A., Vitoshkin I. Current Trends in Laser Welding and Additive Technologies (Review), Applied Mechanics and Technical Physics, vol. 64, pp. 36-59, (2023).
