TY - JOUR

T1 - On the influence of laser beam welding parameters for autogenous AA2198 welded joints

AU - Examilioti, Theano

AU - Kashaev, Nikolai

AU - Enz, Josephin

AU - Klusemann, Benjamin

AU - Alexopoulos, Nikolaos D.

PY - 2020/9/1

Y1 - 2020/9/1

N2 - The effects of different autogenous laser beam welding process parameters on the fusion zone (FZ) geometry, microstructure, and tensile mechanical properties were investigated for 5-mm-thick AA2198 alloy sheets. Porosity formation and hot cracking are observed for low laser powers and welding velocities, while the porosity level is essentially reduced with increasing laser power. The characteristic cross-sectional geometry of the welded joints changes with increasing laser power, taking shapes from narrow V shape to rectangular I shape, and the results are discussed based on the “closed” and “open” keyhole formation during laser beam welding. A methodology is exploited in terms of quantifying the geometrical dimensions of the cross-section of the FZ in order to promote the welded joints with a narrow width as well as with a rectangular shape. The optimal process parameters, leading to FZ close to the desirable rectangular I shape and with a low number of defects, are identified. Microstructural analyses reveal a pronounced transition zone in between the FZ and the heat-affected zone, which is subdivided into two narrow zones, the partially melted zone (PMZ) and the equiaxed zone. The narrow width of the FZ and PMZ, as well as the rectangular shape of the FZ, enables the autogenous welded joint to reach good tensile deformation properties.

AB - The effects of different autogenous laser beam welding process parameters on the fusion zone (FZ) geometry, microstructure, and tensile mechanical properties were investigated for 5-mm-thick AA2198 alloy sheets. Porosity formation and hot cracking are observed for low laser powers and welding velocities, while the porosity level is essentially reduced with increasing laser power. The characteristic cross-sectional geometry of the welded joints changes with increasing laser power, taking shapes from narrow V shape to rectangular I shape, and the results are discussed based on the “closed” and “open” keyhole formation during laser beam welding. A methodology is exploited in terms of quantifying the geometrical dimensions of the cross-section of the FZ in order to promote the welded joints with a narrow width as well as with a rectangular shape. The optimal process parameters, leading to FZ close to the desirable rectangular I shape and with a low number of defects, are identified. Microstructural analyses reveal a pronounced transition zone in between the FZ and the heat-affected zone, which is subdivided into two narrow zones, the partially melted zone (PMZ) and the equiaxed zone. The narrow width of the FZ and PMZ, as well as the rectangular shape of the FZ, enables the autogenous welded joint to reach good tensile deformation properties.

KW - Engineering

KW - AA2198

KW - Aluminum-lithium alloy

KW - Laser beam welding

KW - Microhardness

KW - Tensile strength

UR - http://www.scopus.com/inward/record.url?scp=85090065173&partnerID=8YFLogxK

U2 - 10.1007/s00170-020-05893-8

DO - 10.1007/s00170-020-05893-8

M3 - Journal articles

AN - SCOPUS:85090065173

VL - 110

SP - 2079

EP - 2092

JO - The International Journal of Advanced Manufacturing Technology

JF - The International Journal of Advanced Manufacturing Technology

SN - 0268-3768

IS - 7-8

ER -