An experimental analysis of fatigue behavior of AZ31B magnesium alloy welded joint based on infrared thermography

• The fatigue behavior of AZ31B welded joint was researched by thermography method.
• The theoretical models were formulated to explain the temperature evolution.
• The influence of weld reinforcement on fatigue behavior was investigated.
• Fast and accurately fatigue strength prediction of AZ31B welded joint was made.
• The mean temperature decline caused by thermoelastic effect was discussed.

The fatigue behavior of AZ31B magnesium alloy welded joint during high cycle fatigue test was investigated by infrared thermography. Five stages of superficial temperature evolution were observed: an initial temperature increase, a temperature decline, a temperature equilibrium, an abrupt temperature increase and a temperature drop after the failure. The theoretical models were formulated to explain the observed temperature evolution. The mean temperature decline caused by thermoelastic effect was observed and discussed when the maximum stresses were below 30 MPa. The influence of weld reinforcement on fatigue behavior was also investigated. A good precision was achieved in fatigue strength prediction by means of infrared thermography.