J. Phys. IV France 05 (1995) C2-71-C2-76
A Random Field 3-State Spin Model to Simulate Hysteresis and Avalanches in Martensitic TransformationsJ. Goicoechea and J. Ortín
Departament ECM, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia, Spain
We propose a 3-state spin model to simulate the martensitic transition (MT) between austenite (S = 0) and two different, twin-related, martensitic phases (S=+/-1). The system can be driven by two fields : Δ plays the role of temperature (drives the thermally-induced transition) and H plays the role of an uniaxial stress. Every spin S, in addition, experiences the effect of a static field h, randomly varying from site to site. The model reproduces the avalanche-like kinetics of the MT and the shape of hysteresis cycles. We obtain the phase diagram of the model, study the evolution of X (amount of martensite) and m (total strain) when the system is driven by the two external fields, and discuss the return-point memory properties of the trajectories. Finally, we study the role played by the random field on the statistical distribution of avalanches.
© EDP Sciences 1995