Weakness of the “hot spots” approach to the kinetics of mechanically induced phase transformations

A systematic investigation on different systems has been performed in order to ascertain the possible role of local temperature rise at impacts in the mechanism of mechanically induced phase transformation processes. High-purity commercial powders have been mechanically treated under different milling conditions to study their kinetic behavior. Phase transformations have been correlated to the minimum temperatures needed to trigger the transformation processes under thermal activation conditions. Deep contradictions have arisen in connection with the so-called “hot spots” theory.