Effect of Laser Power and Speed on the Joint Strength of Dissimilar 5052-H32 and 6061-T6 Al Alloys Welded Using a Low Power Fibre Laser
M.F. Jamaludin, A.B. Abdullah, Z. Samad and F. Yusof
Two dissimilar aluminium alloy sheet metal specimens, 5052-H32 and 6061-T6, with thicknesses of 1.0, 1.5 and 2.0 mm, were welded in a buttweld configuration using a low power fibre laser. The design of experiments (DOE) selected is an L422 orthogonal array with the chosen factors of laser power (280 and 310 W) and laser welding speed (10 and 20 mm/s). Nine sets of experiments were conducted to evaluate the laser joining for: (i) Similar alloys of different thicknesses, (ii) different alloys of similar thicknesses; and (iii) different alloys with different thicknesses. The results show that most of the weldments have lower tensile strengths than both the parent materials. The highest joining strengths are achieved for specimens with the thinnest cross-sectional joining interface. Cross-sectional observations of the weld joints show a maximum depth of laser penetration of approximately 0.8 mm. The welding power has a more profound effect on the tensile strength for most of the experiment sets conducted as compared to welding speed. Porosities are observed in most of the welded specimens, which could affect the mechanical and formability performances of the weldments.
Keywords: Fibre laser, aluminium alloy, AA5052-H32, 6061-T6, laser welding, tailor welded blanks (TWB), joint strength, porosity, dissimilar metal welding