Role of Beam Manipulation on Enhancing Keyhole Stability and Producing Defect-Free Laser Welds in Aluminum Alloys

During high power laser welding, laser beam energy densities above 105 W/cm2 result in the evaporation of alloying elements and the formation of a deep and narrow vapor cavity, known as a keyhole. The formation of the high aspect ratio (depth/width) keyhole improves the maximum depth of the weld and the energy efficiency of the laser welding process. However, the keyhole is inherently unstable and will fluctuate in depth, causing the tip of the keyhole to pinch off and form a bubble, which is then trapped in the solidification front. The keyhole is most unstable at the tip because the keyhole curvature (i.e. small keyhole radius) and temperature gradients are very high, requiring higher keyhole wall temperatures and vapor and recoil pressures.

Industry Sponsor: Sandia

Faculty: Todd Palmer (PSU)

Graduate Students: Abhirup Saha

Industry Contact: Jeff Rodelas