Effect of pulsed electromagnetic field treatment on dislocation evolution and subsequent artificial aging behavior of 2195 Al-Li alloy

In this paper, the pulsed electromagnetic field treatment (PEFT) is designed between the pre-stretching and artificial aging of the thermomechanical treatment. Using electron microscopy and hardness test, the effect of the PEFT on dislocation evolution and subsequent artificial aging behavior of spray deposited 2195 Al-Li alloy is studied. The results show that although the PEFT reduces the Vickers microhardness of the specimen, it improves the hardening kinetics and precipitation strengthening of the specimen during the subsequent artificial aging process. Besides, it is found that the PEFT reduces the dislocation density of the pre-stretching specimen and improves the dislocation uniformity. The PEFT makes the T1 precipitate obtained by the subsequent artificial aging process more finely dispersed, a decrease of the average thickness by 57.6%. From simulation combined with theoretical analysis, it is found that the static recovery induced by temperature rise is an important reason for the decrease of dislocation density on the specimen during the PEFT. The magnetically induced stress is an important driving force for a more uniform dislocation distribution. The mechanism of the microstructure evolution of the material is systematically discussed and summarized.