Figure 5

Mechanism of the pressure-induced phase transition based on the Slichter-Drickamer mean-field model. (a,b) Calculated λ-phase fraction (x) versus temperature curves at P = 0.1 MPa (a) and 30 MPa (b). Calculations were performed for the cooling process and the heating process under the conditions of ΔH = 13.7 kJ mol⁻¹, ΔS = 34.6 J K⁻¹ mol⁻¹, γ_b = −2.4 J K⁻¹ mol⁻¹, and γ_c = −0.12 kJ MPa⁻¹ mol⁻¹, while assuming the γ_a value has a normal distribution centered at 12.88 kJ mol⁻¹ with a standard deviation of 0.3 kJ mol⁻¹. (c) Calculated λ-phase and β-phase fractions versus pressure at 300 K.