Plastic versus elastic deformation effects on magnetic Barkhausen noise in steel

Abstract A study was performed to differentiate the effects of elastic and plastic deformation on magnetic Barkhausen noise (MBN) signals. Linear and angular MBN measurements were made on a number of mild steel plate samples subjected to varying degrees of uniaxial elastic and plastic deformation up to ∼40% strain. Elastic strain effects on the MBN energy were determined to be far more significant than plastic strain effects. MBN energy increases in the early plastic deformation region were attributed to a slight increase in elastic strain due to work hardening. Magnetic anisotropy studies indicated that elastic strain significantly alters the magnetic anisotropy ( α ) in the sample, but changes the isotropic signal ( β ) very little. Plastic deformation has a smaller, but apparently opposite effect, in that it appears to change β but has little influence on α . As plastic deformation levels become large, however, behaviour becomes more complex and is less well understood.