Non-spontaneous vz spontaneous...

Mechanical engineer normally does not dare to discuss sub-molecular structures of the matter, following old latin wisdom "Nec sutor supra crepidam...". But he is forced , to forsee and explain the possible causes why and when his design , or another macroscopic object begin to break. Or at least this is expected from him by others...

Thermodynamic science has rule-of-thumb to discern between things which may happen "from themselves" , and those which need a solid kick to make them occur. The difference between such spontaneous and non-spontaneous events is energy requirement to initiate the process, and overall enthropy change ( object +surroundings). Both together say that principally if you expect solid change in the material object , You need to provide solid portion of energy. Subtle exception are , when the object is already on the higher energy level , as a ball on a hilltop, and small push makes it fall. Another example is from chaos theory - when minimal shift in boundary conditions causes serious change of the process outcome.

But neither Gibbs nor Heimholtz equations do not clarify how, without serious delivery of energy, to instruct the matter to arrange crystal grid faults in an organized row ...