Electron beam welding with in situ heat treatment: An effective method for optimization of soft magnetic properties of permalloy

Considering the deterioration of the soft magnetic properties of permalloy welded joints, a method of electron beam welding with in-situ heat treatment was investigated which provided improved soft magnetic properties. After in situ heat treatment, the initial permeability was considerably increased from 3.15 mH/m (71% of base metal) to 5.58 mH/m (130% of base metal), and the saturation flux density was also increased to 746.8 mT higher than that of base metal (703.7 mT). The tenacity of the joint with in situ heat treatment was improved, indicating that the elongation was increased from 32% to 40% after in situ heat treatment. Both soft magnetic property and mechanical property of the joint were optimized after in situ heat treatment. The underlying reason for the property optimization of welded joint with in situ heat treatment was the decrease in dislocations.