Pores in the weld metal lower the mechanical properties of the weld. It is therefore important to understand the pore formation
mechanisms and find procedures that could reduce porosity. This study focused on laser welding of 3 mm thick magnesium alloy
AM50, investigating how different parameters affect porosity formation. Low levels of porosity content were achieved by either
increasing the welding speed or using a two-pass welding approach. It was found that higher welding speeds did not allow pores,
which were pre-existing from the die-casting process, to have sufficient time to coalesce and expand. In the two-pass welding
technique, pores were removed as a result of a degassing process which occurred through the second pass.