Crystal plasticity analysis of stress-assisted martensitic transformation in Ti-10V-2Fe-3Al (wt.%)

A new model based on crystal-plasticity, crystallography, thermodynamics, kinetics and statistics is developed for stress-assisted martensitic transformation. The model includes the essential features of the stress-assisted martensitic transformation, such as: nuclei of progressively lower potency are activated in the course of transformation, the martensite phase appears in the form of thin plates, the parent phase exerts a higher resistance toward the growth of a plate in the thickness than in the radial direction, the average plate size decreases while the average plate aspect ratio increases with the extent of transformation, etc. The model is implemented in the commercial finite element code ABAQUS/Standard to analyze the evolution of martensite, materials texture and the resulting equivalent stress-equivalent strain curve during the stress-assisted martensitic transformation under different stress and strain states in a polycrystalline Ti-10V-2Fe-3Al (wt.%) alloy. The equivalent stress-equivalent strain curves and the volume fraction of martensite-equivalent strain curves are found to be mainly controlled by the applied stress state. Conversely, the texture observed in the transformed Ti-10V-2Fe-3Al is found to be primarily controlled by the imposed macroscopic strain state. The validity of the proposed materials constitutive model has been established by demonstrating a reasonable agreement between the model predictions and the available experimental data. (C) 2000 Kluwer Academic Publishers.