Microscopic Thermo-Mechanical Properties and Phase Transition of Bulk Ice-Ih

The ice–water phase transition of bulk ice could develop with varying temperatures and external loads, significantly affecting its mechanical properties. The coupling effect of temperature and shear loads on the thermo-mechanical properties of bulk ice and its phase transition evolution is poorly understood, especially at the nanoscale. In this study, molecular dynamics (MD) simulation method was employed to investigate the thermo-mechanical behaviours of bulk ice-Ih system at the microscale under various temperatures (73–270 K) and shear paths, where its phase transition, elastic properties, structure deformation mechanism and structural anisotropy were discussed. The simulation results show that (1) the shear modulus, shear strength and ultimate shear strain of bulk ice-Ih system could linearly decrease with rising temperature, aligning with previous studies. (2) Two types of failure modes from bulk ice-Ih system were founded, such as solid–liquid phase co-existence at 73–225 K and liquid phase at 250–270 K. (3) Ice melting into water was attributed to the fracture of hydrogen bond during shear process. (4) Compared to vertical shearing (XZ ($11\overline{2}0$) and YZ ($01\overline{1}0$)) directions, the mechanical response along the horizontal shearing (XY (0001)) direction was most sensitive to temperature effect.