5 DECADES OF THE ZENER EQUATION

The Zener equation was first reported by C. S. Smith in 1948 and since then it has become an integral part of any theory which deals with re covery, recrystallization and grain growth in particle-containing mate rials. Several modifications to the original equation have been made o ver the past five decades to improve its applicability to more realist ic situations. This paper summarises these modifications and discusses which modifications are reasonable and justifiable based on the analy tical models and experimental evidence reported in the literature. Sev eral examples of the applications of the equation are provided to desc ribe annealing phenomena in a wide variety of materials. The paper als o examines the impact of the equation in the field of materials scienc e and engineering and suggests a direction for its future development.