Laser–arc hybrid welding of Ti6Al4V titanium alloy: mechanical characterization of joints and gap tolerance

Abstract

This paper reports the results of a comparison between the mechanical characteristics of butt joints in 3.0 mm thick Ti6Al4V titanium alloy sheets, made by laser welding with no filler material and by laser–arc hybrid welding. Vickers hardness tests have been performed on cross-sections of the beads obtained. In particular, the influence of the gap between the sheets in test welds performed using CO₂ laser–MIG hybrid welding has been analysed. Cross-sections of the weld beads obtained with several different gap sizes have been analysed morphologically. The welded joints have been subjected to draw testing, and joint deformation behaviour has been analysed using an optical deformation measurement system based on stereoscopic image capture (ARAMIS 3D analysis system).

Keywords:

• arc initiation
• butt joints
• CO₂ lasers
• combined processes
• comparisons
• deformation
• efficiency
• gap
• hardness tests
• influencing factors
• laser welding
• mechanical properties
• mechanical tests
• MIG welding
• optics
• tensile tests
• titanium alloys
• tolerances

Acknowledgements

This study is partially funded by the Ministry for Education Universities and Research (Project FIRB RBIP06MYKJ_003). The authors wish to thank R. De Bonis and E. Putignano, CALEF Consortium technical staff, and M.B. Alba, ENEA technician, for their contribution, Chiara Mezzacappa and Giuseppe Perrucci for their contribution in acquisition of the experimental data.