Laser welding of aluminium lithium alloy 8090

Abstract

In recent years there has been extensive research on the development of low density, high specific modulus Al-Li based alloys for aerospace applications. To maximise the number of applications for these materials work has been carried out on the weldability of the Al-Li-Mg-Cu-Zr alloy 8090 using a 5kW CO2 laser. Laser welding was performed on sheets of various thicknesses ranging from 1 to 4 mm. Autogenous, bead on plate welds were achievable at power levels ranging from 1.5 to 3.8 kW and at speeds from 10 to 120 mms−1.Results will be presented to show the influence of welding parameters on the weld shape, grain structure and microstructure. Particular attention has been paid to the formation of porosity in the weld zone. Two principal types of porosity have been identified, pore sizes and volume fractions have been measured and these results will be discussed in terms of keyhole welding mechanisms.In recent years there has been extensive research on the development of low density, high specific modulus Al-Li based alloys for aerospace applications. To maximise the number of applications for these materials work has been carried out on the weldability of the Al-Li-Mg-Cu-Zr alloy 8090 using a 5kW CO2 laser. Laser welding was performed on sheets of various thicknesses ranging from 1 to 4 mm. Autogenous, bead on plate welds were achievable at power levels ranging from 1.5 to 3.8 kW and at speeds from 10 to 120 mms−1.Results will be presented to show the influence of welding parameters on the weld shape, grain structure and microstructure. Particular attention has been paid to the formation of porosity in the weld zone. Two principal types of porosity have been identified, pore sizes and volume fractions have been measured and these results will be discussed in terms of keyhole welding mechanisms.