Carbon emission modeling and mechanical properties of laser, arc and laser–arc hybrid welded aluminum alloy joints

Abstract

Reducing environmental impact while achieving desired processing performance is increasingly sought after. Various welding processes are widely employed in advanced manufacturing, but their carbon emission characteristics vary. However, few studies have compared the carbon emissions of different welding methods. Therefore, it is urgent to analyze the carbon emission characteristics of commonly used welding methods, and to consider the welding performance for a comprehensive comparison. In this study, we construct the carbon emission models of three welding methods (laser, arc, and laser–arc hybrid welding) by building the monitoring platform. The characteristics and proportions of carbon emissions of each system in three welding methods are analyzed. Additionally, the bead morphology, microhardness, and microstructure of aluminum alloy joints are investigated to explain the results of tensile tests. The experimental results show that the appropriate welding heat inputs (WHI) of laser, arc, and laser–arc hybrid welding lead to the ultimate tensile strength (UTS) of 229.1 ± 2.6, 186.1 ± 3.0, and 250.0 ± 0.8 MPa, with the carbon emissions of 43.12, 26.06, and 120.25 g respectively. However, the carbon efficiency of laser–arc welding is lower than laser welding, while arc welding has the lowest carbon efficiency and the highest carbon emission. Increased welding speed can help reduce carbon emissions. For each welding method, properly penetrated joints have better tensile properties than joints with insufficient or excessive WHI, and too high WHI results in low carbon efficiency due to increased carbon emissions and decreased UTS. The welding process with lower WHI help to narrow the fusion zone (FZ) and heat affected zone, and refine the grains in the FZ. This study provides an empirical understanding on the relationship of welding method–carbon emission characteristic–mechanical property.