massive transition

https://doi.org/10.1351/goldbook.M03724
A transition in which a crystal structure is changed into a new structure during cooling or heating, predominantly by interface-controlled reactions and the usual nucleation and growth characteristics associated with thermal diffusion.
Source:
PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 585 (https://doi.org/10.1351/pac199466030577)