EVOLUTION OF MICROSTRUCTURE IN FACE-CENTERED-CUBIC METALS DURING IRRADIATION

When fcc metals and alloys are irradiated at elevated temperatures, th ey tend to evolve toward saturation microstructures that are independe nt of the starting state of the metal and the early details of irradia tion history. This leads to property changes and rates of dimensional change that also eventually become independent of the starting state. The evolution of microstructure in complex alloys, especially during t he transient regime, is usually determined by the complex interaction of many microstructural and microchemical processes. The more complex the alloy, the more difficult it is to identify and define the separat e influence of each participating mechanism. The use of irradiation st udies conducted on simple metals or model alloys assists in understand ing the behavior of alloys of engineering relevance. A review of such studies shows that a number of prevailing perceptions of radiation-ind uced microstructural evolution are not universally correct.