Magnetic properties of the Martensitic transformations with twinned and detwinned

Abstract

The effects of the Austenite (A), twinned Martensite (TM) and detwinned Martensite (DTM) structural transformations on the ferromagnetic properties are investegated by means of the effective field theory developed by Kaneyoshi. We find that the critical Curie temperature of the A, TM and DTM is obtained as T-c(A) < T-c(DTM)< T-c(TM) for H = 0. Thermal magnetization loops are obtained for H not equal 0. The area of the thermal magnetization loops of the A-TM is wider than those of the A-DTM. Paramagnetic Austenite has a phase transition from paramagnetic (PM) phase to ferromagnetic (FM) phase at T-c(TM) and T-c(DTM). The temperature of the As (Austenite start), TMf (twinned Martensite finish) and DTM f (detwinned Martensite finish) increase as the external magnetic field (H) increases. The magnetizations of the A, TM and DTM are the same at low temperature (T < A(s)). The coercive field points are obtained as H-c(A) < H-c(DTM)< H-c(TM). The shearing angle plays very important role in the structural transformations and their ferromagnetic properties, especially in TM.