Evolution of microstructure, porosity and mechanical properties of AZ80 Mg joints during two post-weld processing routes

The evolution of microstructure, porosity and mechanical properties of AZ80 joints during two post-weld processing routes were investigated for comparison. During the partial rolling process, the welding area was effectively strengthened and the porosity was largely reduced with increasing rolling reduction. The Mg17Al12 phases in the fusion zone and heat affected zone were essential on the microstructure evolution during the hot deformation process and subsequent aging process. By proper processing sequence, the strengthening effect of Mg17Al12 phases can be brought into full play, and abnormal grain growth in the heat affected zone can be reduced. The importance of post-weld processing sequence for AZ80 Mg alloy joints was emphasized.