Droplet detachment and motion behaviors in laser-MIG hybrid welding of aluminum alloy

•One droplet transfer cycle can be divided into four distinct phases based on arc morphology and droplet transfer status.•They are (I) wire preheating, (II) droplet formation and detachment, (III) droplet flight, and (IV) droplet fusion into the molten pool.•The first three phases are the major components and determine the droplet transfer frequency.•Laser-arc interaction prolongs phase I and phase III, but shortens phase II.•The mechanisms are due to the metal vapor influencing arc properties and droplet forces.