Influence of Temperature Profile during Laser Welding of Aluminum Alloy 6061 T6 on Microstructure and Mechanical Properties

Abstract

In the present study, laser welding was carried out with CO 2 laser on a 2 mm thick aluminum alloy (6061-T6) sheet to study laser weldability of this heat-treatable aluminum alloy. Screening experiments were performed initially to enumerate the power density requirement for proper coupling of the laser with the material. Bead on plate experiments were conducted to recognize situation under which stable keyhole and welds with minimum defects (porosity and cracks) can be produced. Recognized process window (3 kW power, 4 m/min welding speed, and 18 L/min Helium flow rate) obtained from initial trial was used in butt welding experiment and the resulted weld was characterized by macroscopic and microscopic observation, microhardness study, and tensile test. The microstructure reveals porosity and crack-free welds and hardness data confirmed presence of heat-affected zone (HAZ) and huge drop in overall hardness after welding. After post-weld treatment (aging treatment), the hardness was increased marginally, but base hardness could not be achieved. Thermal profile experienced by the material during welding was calculated and it revealed that the mechanical properties of the material decreased due to temperature experienced by the material lead to loss of aging properties of the material.

Research on Laser-TIG Hybrid Welding of 6061-T6 Aluminum Alloys Joint and Post Heat Treatment

“…They pointed out that the joint obtained with the FSW welding process had better mechanical properties and a narrower heat affected zone than those obtained by the MIG process. Narsimgachary et al [20] welded a 6061-T6 aluminum alloy by the laser welding process and studied the temperature profile on the microstructure and mechanical properties of the joint. Chen Zhang et al [21] used 5-6 kW laser-arc hybrid welding source to weld an AA6082 aluminum alloy, and pointed out that the hybrid welding had some advantages, compared with the joints welded by simple laser or pure arc, such as the higher fatigue limit, lower percent porosity, grains refinement, etc.…”

Process development and coaxial sensing in fiber laser welding of 5754 Al-alloy

“…This allows the achievement of fine welding seam with narrow heat affected zone and very little thermal distortion. 5,6 However, laser beam welding has to deal with many issues that are connected with the properties of the processed material. First of all, the high reflectivity of aluminum and its alloys has been for years a major obstacle to the achievement of consistent laser welding results in terms of quality and productivity.…”

Influence Factors of Aluminum–Slag Interfacial Reaction Under Electric Field

“…As aluminum has become one of the most widely used nonferrous metals [1][2][3][4][5][6], there is an increasing demand for ingots of highly controlled impurity elements [7][8][9]. Electro-slag refining (ESR) is an efficient process for alloy purification and has been extensively applied into steel and titanium refining.…”