Direct observations in the high voltage electron microscope of electron- and ion-beam-induced effects in solids now form a significant part of the research activity at the Argonne National Laboratory High Voltage Electron Microscope Tandem Facility. The programs utilize unique facilities that permit samples held at temperatures between 10 and 1300 K to be bombarded in vacuo with ions having energies between 20 keV and 8 MeV. Instrumentation both internal and external to the high voltage electron microscope has been provided to characterize fully the ion beam at the specimen rod over a wide range of beam intensities. Several studies of radiation damage in pure metals and model alloys that have contributed to an advancement in the understanding of defect production and cascade behavior are reviewed. A recent study of amorphization in a CuBi bilayer film is also given.