Diffusional phase transformation and deformation in steels

Strain accommodation and potential hysteresis of LiFePO4 cathodes during lithium ion insertion/extraction

“…The misfit strain between the triphylite phase (Li 1−y FePO 4 ) and the heterosite phase (Li x FePO 4 ) in nanoLiFePO 4 particles was detected using X-ray diffraction (XRD), [4] and dislocations induced by misfit strain were observed in platelike LiFePO 4 particles using transmission electron microscopy (TEM) [8]. Such a strain-induced energy penalty can decrease the driving energy for phase transformation, [9] resulting in decrease of the phase transformation rate [10]. The accommodation energy decreases the lithiation equilibrium potential [9] but increases the delithiation potential, resulting in an equilibrium potential hysteresis [11].…”

Eddy currents and hardness testing for evaluation of steel decarburizing

“…R is the perfect gas constant equal to 8.314 J/mol K. Nowadays, relations (5) and (6) are well admitted but different values for the diffusivity coefficient can be found in literature. For example, D 0 is equal to 0.1 cm 2 s À1 for Roy and Manna [19] whereas it is equal to 0.234 cm 2 s À1 for Gamsjager et al [20]. It should be noticed that the ratio between these two coefficients gives a value higher than 2.…”

“…Indeed, Golovin et al [23] gives two limits depending on the chromium content in the steel: 135 kJ/mol when no chromium is present and 145 kJ/mol with it. For their part, Gamjager et al [20] and Agren [24] have used 148 kJ/mol and Lan et al [21] and Kumar et al [22], 143.3 kJ/mol. Then, we have retained 145 kJ/mol for Q A in order to take into account presence of chromium in the material (see Table 1).…”

Review on cellular automata simulations of microstructure evolution during metal forming process: Grain coarsening, recrystallization and phase transformation

“…According to Svoboda et al [81] and Gamsjager [82], the chemical driving force F chem can be expressed by…”