S. J. Zinkle

1.03.1 Introduction

Irradiation of materials with particles that are suf­ficiently energetic to create atomic displacements can induce significant microstructural alteration, rang­ing from crystalline-to-amorphous phase transitions to the generation of large concentrations of point defect or solute aggregates in crystalline lattices. These microstructural changes typically cause signifi­cant changes in the physical and mechanical properties of the irradiated material. A variety of advanced mi­crostructural characterization tools are available to examine the microstructural changes induced by par­ticle irradiation, including electron microscopy, atom probe field ion microscopy, X-ray scattering and spec­trometry, Rutherford backscattering spectrometry, nuclear reaction analysis, and neutron scattering and spectrometry. ,2 Numerous reviews, which summarize the microstructural changes in materials associated with electron3-6 and heavy ion or neutron4,7-20 irradi­ation, have been published. These reviews have focused on pure metals5-10,12-14,16,19 as well as model alloys,3,9,13,14 steels,11,20 and ceramic3,4,15,17,18 materials.

In this chapter, the commonly observed defect cluster morphologies produced by particle irradia­tion are summarized and an overview is presented on some of the key physical parameters that have a major influence on microstructural evolution of irradiated materials. The relationship between microstructural changes and evolution of physical and mechanical properties is then summarized, with particular em­phasis on eight key radiation-induced property deg­radation phenomena. Typical examples of irradiated microstructures of metals and ceramic materials are presented. Radiation-induced changes in the micro­structure of organic materials such as polymers are not discussed in this overview.