Effect of Elastic–Plastic Deformation by Biaxial Tension on the Magnetic Characteristics of Nickel

The studies were carried out in a test facility based on the original biaxial testing machine created at the Institute of Engineering Science of the Ural Branch of the Russian Academy of Sciences (IES UB RAS) and designed to determine the physical properties of materials during elastic-plastic deformation independently along two axes. Finite element modeling of the stress-strain state of a cruciform nickel specimen has shown that under symmetric biaxial tension, equivalent von Mises stresses are uniformly distributed over the central part. The results of microstructural studies indicate that dynamic recrystallization occurs in the material during biaxial deformation at room temperature. The results of studying the behavior of hysteretic magnetic characteristics, magnetostriction, Barkhausen magnetic noise parameters, and electromagnetic parameters of nickel under biaxial symmetrical tension are presented. A unique relationship between coercive force and equivalent stresses in the domain of plastic deformation has been revealed. It has been shown that such magnetic parameters as the maximum of differential magnetic permeability and maximum magnetic permeability, as well as the amplitude and frequency of the eddy current signal determined at a frequency of 10 kHz vary monotonically with increasing equivalent stresses under both elastic and plastic deformations.