Effect of the laser power on the microstructure and mechanical properties of the laser-MIG hybrid welding joints of the 2195 Al–Li alloy

Abstract

In the present study, 2195 aluminium-lithium (Al-Li) alloy joints were welded by laser-metal inert gas (laser-MIG) hybrid welding. The effect of different laser powers (700, 1000, and 1300 W) on the microstructures and mechanical properties of the weld joints was investigated. The dendritic solidification structure of the weld joint comprised the α-Al, θ -(Al 2 Cu), and T-(AlLiSi) phases. When the laser power increased, the grains coarsened, and the amount of the precipitated phase decreased. Consequently, the micro-hardness of the weld decreased. The heat input also increased with the increase in laser power. This increased the fluidity and solidification time of the liquid metal at the bottom of the molten pool. Therefore, the deposition of the particles of the refractory metal compounds and the formation of the equiaxed grain zone (EQZ) was hindered.

Effect on the Property of 2195 Al-Li Alloy Laser-Welded Joints with Different Filler Materials

“…For Al-Li alloys, the strengthening phases are mainly AlLiSi, Al 2 Cu, and Al 2 CuLi phases, which are dispersed in the matrix, grain boundaries, and dislocations. These dispersion phases pin the grain boundaries and hinder the movement of dislocations [31]. The precipitates are distributed uniformly in the molten pool by liquid metal with high velocity, which inhibits the EQZ [13].…”

A feasible operational parameter window for enhancement of welding speed in friction stir welding of 2195-T8 Al–Li alloy

“…However, it is very difficult for the conventional fusion welding of Al–Li alloys, due to the high tendency of the formation of solidification defects (welding crack, porosity, etc.) and especially the evaporation of Li element [3]. Therefore, the solid-state friction stir welding (FSW) technology was considered to be a suitable welding method for the Al–Li alloy.…”

Investigation of weld formation and porosity in 5052 aluminium alloy laser-GMA hybrid welding assisted by magnetic field with different orientations

“…Efficient and high-quality welding of aluminium alloy is required because aluminium alloy has benefits of being lightweight, high specific strength, strong corrosion-resistance and low cost [1]. For the welding of medium-thick aluminium alloy plates, the application of arc and laser welding is usually limited by low welding efficiency of arc welding and poor gap adaptability of laser welding [2, 3]. The laser-arc hybrid welding combining the advantages of large penetration, high welding speed and high bridging ability has been widely used in aerospace, shipbuilding, pipelines, rail transit, etc.…”