Problems on the mechanically induced polymorphic transformation

Some typical experimental results are presented and discussed phenomenologically on the topics; (i) the transformations which are readily carried out with the aid of mechanical stimulation but hardly by simple heating (PbO, ZnS); (ii) formation of metastable phases under the influence of mechanical stresses from the phase which is stable at room temperature under the atmospheric pressure (CdS, CdSe); (iii) pseudo-equilibrium between polymorphs during grinding (CaCO₃).