DECALESCENCE

decalescence

(noun) phenomenon that occurs when a metal is being heated and there is a sudden slowing in the rate of temperature increase; slowing is caused by a change in the internal crystal structure of the metal

Source: WordNet® 3.1

Noun

decalescence (countable and uncountable, plural decalescences)

A decrease in temperature that occurs while heating metal through a range of temperatures in which change in structure occurs.

Source: Wiktionary